Because the implication was there. Familiars are not helpful or not very helpful in a number of circumstances (Certamen, Fatigue use, Sensory Magic, writing). That happens to have enormous overlap with where Bjornaer shine. So if we're looking at how big a drawback not having a Familiar is, we're ignoring a good portion of the categories where Bjornaer shine. If we ignore a good portion of where Bjornaer shine, of course they'll be much worse.
Not really, just very early on. Bear just gives you an earlier start than rabbit does.
Not really. Time, yes. Vis and Warping Points are unnecessary. Flaws are only if you decide you really want them for some reason; there's no need at all for them.
Yup. The point is none given the same time and resources can be as a good as a Bjornaer in the areas in which Bjornaer shine. I.e. they have niches where they are the best as a result of Heartbeast and despite the loss of a Familiar.
Yes and no. And that was my point above. If this is the issue, then we're back to asking why the Bjornaer needs to be potentially better at everything? Verditius can be the best at crafting items, Bjornaer can be the best at Certamen and Fatigue use and Sensory Magic and writing, Criamon can be the best at lore and Twilight, etc. Many Houses are just average at everything but lack drawbacks, so you can tailor them broadly, but rarely to be truly the best at something.
What would you say to someone who takes Mercurian Magic because they want a Ritual caster and then complain about how weak being limited to Ceremonial Spontaneous Magic is? You can be the best at something by being worse in other areas.