I fall asleep to documentaries. I don't want to loop one video. I want to play videos that relate to one another and not go from one topic to one completely unrelated. The only way to reliably do this is to use a playlist, which sucks, because not every channel makes playlists and I'm sometimes fine with the channel changing, as long as it doesn't go from #SpaceScience to #WW2againagaingain.
And then I'd say about 30% of the time it'll grab some documentary/video I've already watched, which is also annoying.