Comment by rdsubhas
> various "benchmarks" JpegXL seems just be flat out better than WebP
The decode speed benchmarks are misleading. WebP has been hardware accelerated since 2013 in Android and 2020 in Apple devices. Due to existing hardware capabilities, real users will _always_ experience better performance and battery life with webp.
JXL is more about future-proofing. Bit depth, Wide gamut HDR, Progressive decoding, Animation, Transparency, etc.
JXL does flat out beats AVIF (the image codec, not videos) today. AVIF also pretty much doesn't have hardware decoding in modern phones yet. It makes sense to invest NOW in JXL than on AVIF.
For what people use today - unfortunately there is no significant case to beat WebP with the existing momentum. The size vs perceptive quality tradeoffs are not significantly different. For users, things will get worse (worser decode speeds & battery life due to lack of hardware decode) before it gets better. That can take many years – because hey, more features in JXL also means translating that to hardware die space will take more time. Just the software side of things is only now picking up.
But for what we all need – it's really necessary to start the JXL journey now.