Con: Doesn't Work.
Pro: Doesn't make Youtube pages unusable like UDL Helper.

Small size means it's quick to install and UNinstall if it makes every Youtube page unusable within 5 - 10 seconds without even clicking anything on the page like it did for me.
(Uninstalled and reinstalled 2 more times, tried on two different pages, and it was the same every time. Pages worked fine once I uninstalled the extension.)