Didn't they turn this on by default?
If websites owners truly wanted it, it would be a 'do thing to opt in' and everyone would rush to that.
Now I do think this kind of thing is good for many reasons, but I also see many reasons this can be problematic (that I did not consider the first time I read about it).
I myself would prefer an option to throttle the bots, and give them a 'you can spider at 2am-5am once per month access' via robots.txt, header or something..
you come more than twice in a month and get blocked or pay for access to static version hosted on other server / cdn..
best of both worlds without some of the negative issues.
Otherwise it's a play that helps cloudflare more than anyone else, and hurts more than [open][other][AI] - etc. imho.