I like the Conscientiousness rewarding in the story too. I don't understand what it has to do with whether or not they get information from books though. There's a line somewhere in the text that almost literally says magic can only be passed from one living mind to another because of the Interdict of Merlin. So, unfortunately, reading doesn't seem to do much besides make you better at what you've already heard about from living teachers.

Riddles would be an interesting workaround, but nothing we've yet seen implies that works. And, there's not a relevant difference between simply reading something and solving a riddle - both use your mind, but apparently that isn't enough to get around the interdict of Merlin.