Why do you need to be on Mars to do that? It's simpler to do everything in orbit, which is the real gate to the asteroid belt. Or directly establish bases in the belt, if we knew how.
Yes, that's also certainly an option. Still, it seems to me that a lot of people still can't really think in terms of space only infra and "a hight tech city, but on Mars/Moon" gets them to a more familiar context.
So I think it makes sense to talk also about surface bases, to get more people on board, even if those are potentially quite inefficient.
