I haven't seen the movie BLACK PANTHER, but my understanding is it's aspirational, like Wonder Woman with the Amazons. It presents an idealized society. Something to aim for. So that's what I mean by aspirational.
With a black Superman that might mean showing people of colour on Krypton living in a kind of Camelot. Or it might mean that in this alternate reality U.S.A., peace and understanding has been achieved. It sets an example for people, to show how we can be better and do the right thing. I don't see that as fluff. It's the opposite--it's what we all are here to do--to make the world a better place.