When I first looked at these two virtues ( Elemental Magic and Secondary Insight ), I thought, wow do these virtues really go well beyond the average. Match an affinity or two in the mix and you are really powering up the xp.
I then took a couple more reads of the virtues to look at them more carefully to see what was being worded.
"Whenever you successfully study one of these arts, you gain an additional point in each of the other three."
From the wording, I interpret that if you study a book on Igneum and gain 6 xp for Igneum then you also gain 1 xp in Terrum, Aquam, and Auram ( not 6 xp in each which some players may try to convince you but point out that article "an" is singular as is "point". )
This is even more clear in specifying that each period of study awards a "single" experience point in either 4 different forms or 2 different techniques.
Note: these are both Major Virtues and each season of study is awarding a bonus of 3 xp for elemental or 2-4 xp for secondary insight.
I would be more pointing out that the Minor Virtue Apt Student awards a bonus 5 xp per season if you have a teacher ( no restriction of art or ability but it does require having that teacher which might be harder to come by ).
Book Learner is a Minor Virtue and each season of study is awarding a bonus of 3 xp if studying from a book. The same basic advantage is from Free Study and is a minor Virtue.
The xp gain is thus not unbalanced compared to the minor virtues that can give a similar bonus.
The question then is why are Elemental Study and Secondary Insight Major Virtues if Minor Virtues can give the same gain in xp?
The answer is that Elemental Study and Secondary Insight apply if you study from a Teacher, Book, or Raw Vis. Their application to all three circumstances equals the purchasing of the three minor virtues of Book Learner, Free Study, and Apt Student.
The selecting of the virtue Elemental also gives a bonus on flexability with requisites which makes it useful if a magi wants to do things like have flaming guysers of water or changing raindrops to pellets of gold.
Secondary Insight gives the advantage of flexability where the additional xp are awarded which means that you can focus on one or two main arts and still reach the minimum xp to qualify to have an apprentice in arts that you might not have study material to work from.