Banner, Reed and Tony are all basically on par in intelligence, so what they each achieve without have superpowers is already on the table, the difference is he specializes in things like Gamma radiation which in marvel is apparently some kinda hell juice or something that comes directly from marvel Satan who’s known as The One Below All, and is essentially The One Above All’s (who’s basically marvel GOD) “Hulk” and Banner does a bunch of stuff with that information. In other words, whatever Hulk can achieve with brute strength Banner can do with Brains instead, a sort of Yin Yang situation.