It's very helpful. I remember I posted a request to get it on the new Edge when it first appeared on Google Chrome Canary but the Devs said it's not part of the chromium but rather a Google-only feature. however you've done a great job implementing your own version of it, the button works great, it's in sync with Windows 10's built in media controls too (the one that appears when you use media buttons on your physical keyboard like next/prev/pause buttons)
not to mention that it took only 3 days for you to implement it in the new Edge Canary. in Google chrome canary when it was first introduced it had serious bugs for a week, for example using next/prev buttons would crash the whole browser.
So far I only found one issue with it. on Twich videos streams, there is no background in the Global Media Controls, it's just white in all live streams, same thing applies to Vimeo videos.
Thank you! In the last 2 weeks since Global Media Controls button was added I tried a lot of websites and none of them has shown background thumbnail in that area (see the picture) except for YouTube, all the rest use the white background.