If I'm not mistaken, Webtorrent seems to let you stream. As for HLS... it'd nice to have, sure. But not having it would still beat not having anything, wouldn't it?

It looks like webtorrent does let you preferentially pull blocks--TIL. That said, you're reliant on them being available on demand. Social media is almost definitionally herding. Adaptive streaming is 100% not a nice-to-have, though. It's absolutely necessary, or it goes to shit on a phone.