There's system level support for WebP in Mac Big Sur. Also Safari 14 supports it.
I don't like it because WebP doesn't add anything else than better compression compared to PNG and JPEG. AVIF or JPEG XL bring HDR support, so Apple should have adopted one of them. Even Google is planning WebP 2.0 because they noticed that WebP isn't enough: https://www.youtube.com/watch?v=zogxpP2lm-o
WebP does add something more than better compression (unless you can live with enormous PNGs): efficient compression of lossless photographs, lossy diagrams and photographs with alpha channels.
WebP also has an unfortunately low maximum image resolution. I was trying to convert some webcomics pngs to lossy WebP for reading offline, and couldn't because the images were simply too tall to save in WebP format without resizing/cropping.
I don't like it because WebP doesn't add anything else than better compression compared to PNG and JPEG. AVIF or JPEG XL bring HDR support, so Apple should have adopted one of them. Even Google is planning WebP 2.0 because they noticed that WebP isn't enough: https://www.youtube.com/watch?v=zogxpP2lm-o