I suggest updating your "why should I use it" section then. I also saw a trivial polyfill and stopped reading. I also like the idea of an option to fall back t

I suggest updating your "why should I use it" section then. I also saw a trivial polyfill and stopped reading. I also like the idea of an option to fall back to making the element fill the page if the browser doesn't support the fullscreen API. You could even breifly display the hotkey to put the browser window in fullscreen if it supports it.