From a conversation with Shane regarding putting a font-size on a div:
Base components, although as reusable as we try to design them to be, do require tweaks here and there to fit certain presentations. We'll do this quite often, I'm sure; however, if I had utilized font sizes on containers and inheritance, it would be easier to overwrite base components typography in special use cases because you wouldn't have to get super specific.
From a conversation with Shane regarding putting a font-size on a div: