I just discovered that even Edge now supports animated PNG:
https://caniuse.com/#feat=apng

And now that Win7 has officially hit unsupported status which automatically rules out IE11 as a being a valid excuse, there's pretty much no reason to keep using GIF on the internet now (unless the web server is dumb and insists on re-encoding everything, thereby stripping out APNG's animation).

So on the subject of APNG, here's a basic 3-frame animation I made 18 months ago out of short a sequence Anguro did:
https://www.gurochan.cx/art/res/14876.html#23018

Now if only pixiv's Ugoira was more than what is effectively motion JPEG implemented via javascript which is like inefficiency squared.