I really enjoy this as a feature. There are many times that I don't need a video full frame, but don't want to see the rest of the website page either (I'm looking at you YouTube). I can just pop the video out, and even shrink its size, and then go back to whatever else I need to be looking at.

Sadly, there are so many videos out there that do not need to be videos, yet that's how they are presented for sometimes rational reasons on the "creator's" part.