Until you want to watch a playlist or a channel without choosing each video each time.

Feather Beta doesn't work with the "Play all" links or playlists in general.

I created a little thing for making and sharing playlists: http://www.cueyoutube.com/

I tweet my lists using the hashtag #cueyoutube which means I can always go back and find them later using http://snapbird.org/

This is the problem I ran into, I originally enabled it think it was great and the next day promptly disabled it because of this.