For the 10% of places where something lawn-like just grows naturally, without extra watering and extra work, sure. But for the other 90% of lawns…

It's much more than 10% of the places where lawn is grown. Much of mainland Europe has native grasses used for lawns everywhere.

I dunno. Maybe walking barefoot in the summer isn’t that important?

Neither are most things, but life is about enjoying the little things, and that's a very enjoyable one for some people. And it's free (well at least if you're privileged or cursed enough to have a detached home with a garden, I grew up in such a house and hey, a few decades later the same lawn is still going strong unlike the rest of the house, it's been watered on average maybe 5 times a decade if not less).

This hatred of lawns seems like yet another super America-specific thing, as North America has a lot of dry areas I guess. You know that super controversial Kentucky bluegrass that's not native and all the anti-lawn folk hate? It's native to basically all of Europe, parts of Africa and parts of Asia. Most meadows here have tons of that, along with clover which is also in some lawn mixes (and great for the bees, who are also not invasive here), dandelions which nobody plants on their lawns, but are unavoidable anyway, etc. Your average lawn is basically a mix of many of the same plants that would naturally occur in a meadow, but trimmed short.