Personally, I use it for a chronological feed of my subscriptions. It takes less time to find something worth watching, and it is easier to move on to do something else if there isn't anything worth watching.

Bookmarking or downloading interesting videos is also handy, since they aren't mixed in with my general bookmarks (in a web browser).

> I use it for a chronological feed of my subscriptions.

YouTube provides RSS feeds. You could use an RSS reader to subscribe to your channels. I do, it's marvellous.

On mobile I use PipePipe for listening to stuff (like presentation videos) in the background and downloading offline audio and video.