The answer to the second question is obviously "Because the author thought it did apply", and it didn't seem obviously stupid to playtesters or the editor.
The answer to the first question is harder. Major Magical Focus in metals, or Minor Magical Focus in gold, suddenly becomes an uber-enchanter Virtue. This is not necessarily a critical problem, although it makes Foci that could be things-to-be-enchanted much more potent than ones that could not, which is an issue.
Maybe we need a new Virtue that is basically a Focus for enchanting particular kinds of things. "Swords", "staffs", "Preciouses… er… rings". I think that would be a Minor Virtue, could be called Enchanting Focus, and could then be errata'd into the Confraternity of Roland.
It's far from obvious. When I read the chapter, I simply assumed that the focus in swords of the Confraternity meant they were really good at producing effects that affected swords. Many would be enchanted in the swords themselves (say, a sword that keeps fighting on its own, or becomes supernaturally sharp). Many would help the confraternity act on existing swords (say, ensuring that no sword ever cuts you, or keeping track where a sword you made is and what use it's being put to). More in general, if you are a swordsmith magus, it seems natural that your Circling Winds of Protection should be Circling Swords of Protection. It never occurred to me until reading it on the forum that if I wanted to make a sword that can cast The Seven League Stride, The Invisible Eye Revealed, and the Incantation of Lightning, such a minor focus would apply -- and as far as I can tell there is nothing in any rulebook saying so (so no need for errata).
I think allowing a focus to apply to enchanting into an item effects that are totally unrelated is a terrible, terrible idea.
First of all, it's incoherent: if a focus in swords applies when you to enchant incantation of lightning in swords, a focus in women should apply when a maga researches and casts the incantation of lightning, and a focus in roses should apply to all magic of a magus whose sigil is roses.
Second (and this applies to the proposed Minor Virtue too): it just runs against the notion of Focus. Your magic is not really Focused, it just faces Deleterious repercussions when you can't use certain vessels for its enchantments.
Finally, it gives even more power to magi focused on enchantment, who have slowly grown in power over the life of the line as bonuses to their work just piled up -- and are not limited by the 10 magnitude cap for non-ritualist casters.
I personally believe the system is working as it should currently, and the focus should only apply to the power, not the shape of the device being worked on. For the contra fraternity of Rolland this means that they can enchant swords to be awesome swords, rather than creating swords that function as wands and are, in effect, never going to be used as swords.
So long as the effect is enchanting is effecting the sword (making it unbreakable, making it on fire, etc) then the focus applies from what I remember, which is in flavour and feels right - giving them a bonus to enchantment when the item is a sword creates the old problem of 'when you have a hammer everything is a nail' - only in this case when you have an enchanted item it's always a sword.
In my mind the Contrafraternity has the focus on swords because they want to make awesome swords, so effects targeting the sword they are enchanting is both mechanically fitting and flavourful.
That would be better! Enchanting (and Verditius enchanting even more so) is already so full of +x to Lab total bonuses that one more is both uninteresting and power-creepy. Reducing the amount of vis to open an enchantment goes into another direction, although not a completely new one.
Another possibility would be some Virtue that makes the stuff that you enchant mundanely better, as if crafted by a craftsman of higher skill.
Sort of, not quite. They allow you to apply an appropriate S&M bonus of the item to mundane activities -- e.g. a sword's S&M to harm others. No, here I meant something like "the more you enchant an object, the more it becomes a Superior/Excellent item as per C&G rules" (or perhaps it becomes more beautiful, as per A&A rules).
As someone who regularly plays Verditius magi, I have to (very emphatically) say: NO thanks.
My troupe already complains that there's really no reason for them to make devices of their own, ever. Because it's just more efficient to pay the verditius.
I can regularly enchant lesser devices with effects that my colleagues would be hard pressed to invent from lab texts - I really don't need another bonus to my lab total.
And that is in a saga/troupe that absolutely agrees with @ezzelino's first post above.
Familiars pg 105 of the core book says that "Foci that cover the familiar apply to the investment of all powers, no matter what they do. Foci that cover the power apply as normal."
My troupe has taken that to mean that the same applies to enchanted devices.
In my troupe we run it as a major focus in "metal" doesn't apply if you have an iron wand and then its filled with a bunch of gems, unless you're only opening/enchanting the metal part and the gems/other materials are just aesthetic and not going to give any bonus.
Edit: a focus in metal giving a bonus no matter what power you put in, seems fine (seeing as its fine for familiars though they do have restrictions) because its a focus and only ever doubles the lowest art. Verditius Prime has a focus in metal, so he makes a metal wand. He gets to double the lowest art on any effect he puts into that wand. Sounds super strong on paper, but in effect anything that isn't Terram based is bad and he gets a big +1 to putting CrHe effects into it. It's weakness is the same as all foci: its only as good as your lowest art.
Afaik even Verditius still pay full vis cost for the effects they put into items so sure, they get a big lab total so they can put a 10 magnitude effect in, they still have to pay 5 vis for that.
On a closely related topic, I have seen many people in discussions here wonder "Why take 'Wooden Wands' as a Minor Magical Focus, when 'Wood' already exists as a Minor Magical Focus?"
My answer to that would be that while a plain wooden wand also counts as wood, a wooden wand inlaid with gold and tipped with a ruby is still a wooden wand but it does not count as wood. So if you want to take advantage of Shape&Material bonuses the narrower focus could sometimes be more desirable.
As regards having a magical focus apply to all effects invested in an enchanted device, many people think it would be too powerful. But would it really be all that powerful?
Sure, a Verditius mage (or some other enchantment specialist) could get really high Lab Totals this way when creating their devices, but how often is the Lab Total the limiting factor when creating enchanted devices?
Most often it seems to be Magic Theory and/or getting hold of enough vis that sets the limits.
Pretty much always when you're making a Lesser Enchanted Device, and those are the best to make in general because they save vis and seasons. The only times to specifically want to avoid them are when you're working on your Talisman or when you just need a bunch of effects connected to each other for whatever reason (I can think of a few general categories.). But most things should be made as Lesser Enchanted Devices if possible.
If you doubt Lab Total is the limiting factor, consider the even the lowest end of vis limits. E.g. A level-60 Lesser Enchanted Device requires 6 pawns of vis, manageable by pretty much any beginning magus and not so overly expensive; but it requires a 120 Lab Total.
True, Lab Total can very much limit if you can make something as a Lesser Enchanted Device or not.
This does not let you make more powerful enchanted devices than you otherwise could, but lets you make them in less time and with less vis - which admittedly can be quite important.
Given the sheer number of Verditius-exclusive enchanting tricks that are allowed to exist, I would be opposed to removing one of the relatively few that are open to enchanters from other houses, even if those tricks also benefit Verditii.
I'm not worried about making the Verditii ridiculously powerful; they already bloody are, this is apparently working as intended, and concern over yet one more bonus (even a large one!) is...very much shutting the stable door after the steed is stolen, if you're worried about Verditius power levels.
I would very much like non-Verditius magi to be allowed to be competent and even genuinely strong enchanters within their specialties, and find very little if any harm in allowing those specialties to be interpreted broadly.
For what it's worth, I think ezzelino hit it on the head: Magical Focus should only apply to the effect, not the form.
mMF (Swords) would let you enchant a sword to never break, stay sharp, fight on its own, be wreathed in fire. It would let you enchant a shield that makes any sword that hits it break. It would allow you to make a Crystal Dart Variant that shoots Swords. I might even be cool letting someone shoot lightning from their sword if it was appropriately thematic.
But it would not apply to just enchanting flight or the ability to see through smoke into your sword.
I am not viscerally opposed to Enchanting Focus as you have described it, but I would probably recommend that Magical Focus or Enchanting Focus applies to enchanting lab totals, but not both. The downside of Enchanting Focus is that it feels like it could be a boring numbers bump without thematics, but I think it also does offer some cool specialization.
Im a little torn, but don't see a major downside of adding it. It really just allows non-Verditius access to some crafting specializations, which is nice.
There's one huge catch here.You are not investing powers into the familiar. You are investing them into the bond. Powers in the bond have to affect either the familiar, the magus, or both. So in some sense -- particularly given how the bond... well, bonds magus and familiar -- the focus applies because the target of the power is covered by the focus, rather than because the vessel is.
There's another catch: familar bonds are not cumulative with Verditius magic. This has to do more with mechanical balance than with the conceptual "correctness".