Savants

Question: In game, do you learn new boons for your purviews automatically by purchasing them, or do you actually have to make a play of going and learning them?

Happily for today's modern, on-the-go Scion, you can learn boons as you purchase them; there's no in-game requirement for doing so. Being magical and awesome is literally in a Scion's blood; while we definitely don't discourage players from coming up with cool reasons why this particular power is manifesting at this particular time, it's also perfectly permissible for your divine blood to spontaneously grant access to new powers that you are attempting to learn or have a natural predisposition toward.

At the Hero level, this is limited somewhat by the need for a Birthright with that purview on it; you could buy all the Sky boons you wanted, but if you didn't have a relic with Sky on it, they would be totally useless. At Demigod and past, though, you can develop any power you like even if you don't have a relic for it; the cosmic powers of purviews are universal to all gods and don't require teachers or experience (though I'm sure neither hurts!). They're not really knowledge that has to be learned so much as power that has to be manifested, which is what you purchasing them with XP really represents.

Scions can, of course, also seek out teachers, wise mentors or famous figures who have the powers they hope to develop; it's not strictly necessary, but doing so often earns them lots of tips and connections to other deities and creatures that may be useful later. Practice can be great for Scions growing new powers, too; the more Fire mortals see you practicing, the more likely they are to be Fatebound into believing you're good at Fire, thus helping make gaining new Fire boons part of your very Fate.