Well Google said otherwise when they removed support for it: https://storage.googleapis.com/avif-comparison/index.html

However I’m not sure how trustworty their own statistic is.

On the other hand Mozilla’s PoV:

neutral - JPEG-XL includes features and performance that might differentiate it from other formats, but the benefits it provides are not significant enough on their own to justify the cost of adding another C++ image decoder to browsers. A memory-safe decoder would reduce these costs considerably, and we are open to shipping one that meets our requirements.

https://mozilla.github.io/standards-positions/

So AV1 is clearly the winner here, also because it can be used for videos and not just images.