DefinitelyNotAPenguin

No cause they want to be able to prevent people from adding ads and tracking to the app and then redistributing it.

He talks about this in the announcement video.

Youtube has just began fighting real hard against adblocking so ublock has to update their solution constantly.

I blocked the overlay too and could play the video and interact but couldn't scroll.

They've only just recently started rolling it out

That doesn't really work, it ends up breaking and not letting you scroll the page.

Youtube keeps updating their anti adblock so ublock keeps having to update, it's a silly arms race.