Did not work for me, however it may work for others =)

It works, but, if you play a playlist, and then skip to a different song - the switch is still ON, but the video won't repeat, the next one will play. You need to turn it off and then on again to have it work. Nonetheless, five stars because: 1. it works; 2. it has a really nice, clean UI, looks like a feature added by YT; 3. doesn't need excessive amount of weird permissions; 4. no delay between ending a song and playing it again, no page restart etc.; 5. if you turn it OFF on a video in playlist, the next one will play (in some other addons, it's not always a given) :)