Animated WebP is based on VP8. However, the alpha channel is stored losslessly, which makes compression even worse than VP8.
VP8 is of course a generation behind VP9, so the results will be significantly worse than the VP9 example in the article, which is significantly worse than AV1.
Also, the demo crashes Safari for me (it plays progressively slower and slower).
Animated WebP is an absolute dumpster fire on mobile safari (and thus all iOS derived browsers based on WebKit), with the animation often stuttering and dropping frames before it corrects itself.
I had to revert back to autoplaying no-audio MP4 files for this reason.
VP8 is of course a generation behind VP9, so the results will be significantly worse than the VP9 example in the article, which is significantly worse than AV1.
Also, the demo crashes Safari for me (it plays progressively slower and slower).