Learning Usefulness?

[UndergroundMan]

So I've beat the game on Paladin and now want to try a Mage playthrough, and I'm curious if Learning 3/3 is considered a "must have" for Mages. Though mind runes aren't quite as rare as might, they're still aren't so common that investing like 30 of them in a skill seems appealing if it doesn't directly aid me. So anyone who has played on Mage is Learning still worth maxing? (Note: I'm not trying to do max level on impossible or anything crazy like that)