It does what it says perfectly, but I wish it also displayed a button on video player page (for example, next to Share button, or next to the autoplay toggle button). Two reasons for it:
1) I keep forgetting what the shortcut is and I shouldn't have to memorize it.
2) Surely it's faster to just click one button than press 3 keys on a keyboard (much more than 3 when you keep trying to guess the correct combo).