I think it's a sensible feature but should have been added just as a button on the standard video controls and as part of the right click menu. If a website goes out of the way to abstract both of those things into site controls then the browser shouldn't be adding additional menus on top to try to get around it it should let the site decide to add the button or not.

A great example is Twitch (which I would have assumed was one of the prime use/test cases). Twitch has these things they call "extensions" that streamers can add to the player of anyone watching the stream... and they pop out on hover from the right when you want to access their main settings. So instead of clicking the button to modify the extension suddenly the video is in the corner of my monitor.

That's when I decided to disable it for now :).

Edit: clarification