I think their first game with this feature was Bayonetta (https://www.youtube.com/watch?v=_6nkc6GQ-B8) but at this point a bunch of other games have it. I think every action game should have this where possible, and you can find testimonials out there from people who love these features despite not having major accessibility concerns, like https://www.vice.com/en/article/xgx8nz/auto-battle-is-the-be...
Increasingly I think we're discovering that there's a class of temporary accessibility issues that can get in the way of using a website or video game - you have trouble focusing because your kids are distracting you, you can't remember what your current objective is because the last time you played was a week ago, etc. It's great for games to provide assistance in those cases too.
I mean I won't claim they're fun, just that they're easy to play.
I think anything that can be co-piloted so smooth that other player is not annoyed, can be also simulated by an AI.
It is not really overthinking it. It is taking the learning and bringing it to a wider audience.
But there are a lot of affordances devs can make in individual games. Someone else mentioned Celeste and Last of Us, but Microsoft's Forza series has a bunch of options, like brake assist or turning assist, that can take a lot off your plate.
Usually, when these modes are enabled, there is some indication that they are used, and you can't enter ladders with them, to prevent cheating.