Agree with decode time being more important. There we still can improve. We have ideas how to make it faster than WebP lossless, but haven't engaged with that

Agree with decode time being more important. There we still can improve. We have ideas how to make it faster than WebP lossless, but haven't engaged with that yet -- the lossless decoding is already fast enough not to be a blocker. Also, given how efficient and quality-sure the lossy is, it will become tempting to migrate many of the PNG/GIF/WebP lossless cases to JPEG XL lossy further reducing the priority in JPEG XL lossless. This can be a 4x-5x savings whereas a better lossless is only 10-40 % savings in density.