Judging by the fact that almost nobody in the mainstream talked about this until a week leading up to the mission, and that it’s been 10+ years in the making, I doubt it’s some vanity thing.

I don’t see how anything as substantive like this can be seen as “vanity” (unless you mean to count that as a bonus).

It’s amazing to see NASA doing newer great things (Webb, Mars probes, all have been incredibly cool too, but manned stuff always hits a different note). Yes they’re way more expensive than SpaceX, I get all that. But it’s nice to see something so overwhelmingly positive and a true example of human ingenuity, collaboration, and bravery, that we need a lot more of that to remind us these days of the positive times we live in.

And the fact that we did this 50 years ago, at least to me, means I appreciate even more how we got it done with that age’s technology and knowledge the first time.

The answer in the 60s was "to beat the Soviets". Today, we are partially doing it to beat China, but we really are gearing up for Mars.

You can't just start from zero and fly to Mars. You need to build an entire workforce able to produce and operate fantastically complicated machines. And you need to fly regular missions, each more ambitious than the last, until finally we can land people on the Red Planet.

Artemis II is the beginning.