Generics are useful in two ways: you can send them out for Propositions, and they are cool aesthetically since their character design changes with their class while nongenerics do not.

And they're no reason to stick with the Generics the game gives you. You can pitch them and recruit your own. I like starting out with four Generics with Brave and Faith of 70 each. You can tweak Brave and Faith eventually, but I like going out the gate with high stats.