Edit- I was unaware the recently-announced Safari 14 Technical Preview adds support for WebP too! Making both formats viable for all browsers, finally.
Recently we've been going through the browser stats on our websites, and while globally apparently IE is dying, it's certainly not dead yet. In the specific industry I work in (Heavy Automotive Retailing, eg Truck Sales and Servicing), we see upwards of 30% of our users on browsers <= IE11. All of our sites are getting poor lighthouse scores on performance with the main suggestion to be changing to webp, but that would exclude 30% of our customers.
https://caniuse.com/#search=animated%20png
Edit- I was unaware the recently-announced Safari 14 Technical Preview adds support for WebP too! Making both formats viable for all browsers, finally.