The only insane thing is to have an algorithm guess whether I want to watch the video or not, instead of just letting me decide with a single damn click.

Autoplaying videos that stop playing after scrolling is one of the worst UX crimes in history of UX. At the same time in 2022 I still cannot prevent "autoplay" of animated gifs that bombard my senses in every feed unless I outright block literally everything other than text.

And the sad thing is that software quality in general is most likely just as bad, only not as visible.

There's a bit more subtlety and tradeoff here.

For example, I doubt most people watching a video on YouTube would like the video to stop playing when they scroll down. If they wanted to pause it, they'd pause it. They also probably don't want the video to transition to the next, whilst they're reading threads.

If you're in an infinite loop stream however, you do probably want it to pause or stop, without intervention, as you've scrolled away and dismissed the video.

However - you may not want that to happen whilst you're still in-thread with the video. If you're looking at comments on the video, you probably still want it to continue. But if you reach the bottom of the thread, you probably don't want to have it pause and have to find the start of the thread to continue playing it, just because you scrolled an inch too far.

That's fair, as always context matters. But I feel it was implied the context of our discussion was infinite scroll pages like twitter (he specifically mentioned that), tiktok, instagram etc.

That's true - which is why I spent the majority of the comment speaking about a situation in an infinite scroll where you do not want the video to automatically pause.

Why decide? Gimme a toggle in the settings to pause or throw it into the corner when I scroll past a video I've pressed play on

Personally I prefer it to pause, but I don't really watch many videos on Twitter

not op, but yes when I actively unmuted it, it should keep playing