Good idea, but as of Mar 26, the button shows up, but clicking it does not remove the video from the playlist.

The Trash Icon did show up after restarting the browser and it makes cleaning the playlist much easier.
I prefer it over those other ones that auto remove watched videos as i sometimes watch same video multiple times.

亲测好用！

Didn't work for me. I can see the trash icons but clicking them doesn't work.