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.
In what concerns Android, Google would could have done better for WebP adoption than just dump a sample into Github and hope for the best.
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