Yes, with Firefox adding support Jan 2019 and Safari last September, and it being very useful for Discourse Gifs component, I worked on adding support for it on the main places in Discourse.
We still fail to resize animated images (like if you want to use an animated webp avatar), but it works fine as a the standard post upload.
It’s a really good format for lossy/lossless animated images, with most of the gains of video-gifs without most of the downsides.