It's implemented nearly everywhere (firefox, ffmpeg, edge, chrome, opera, vlc,...) and the spec is 100% final. Problem is that (and now the everywhere gets weak) android didn't implement it yet (afaik) and some packaged versions of the software haven't got it enabled or are just out of date.
What we can get from the article thought is: why isn't gif replaced by webm/vp9 yet? Can be encoded in no time and is actually supported everywhere.