I can accept a claim that JPEG-XL is not the best format for it, or that it is good, but not worth the complexity and extra surface area it introduces. I can not accept a claim that "lossless just isn't very useful on the web".
I think its correct to say a use case that is very niche on the web isn't super important to the web. Especially when there already exists a bunch of lossless formats. After all, the value proposition of jxl is to save some bytes. It would be different if the point was introducing images as a whole.
> Especially when there already exists a bunch of lossless formats.
Sure, but I'm not defending JXL here in particular, just arguing against the point that lossless images are unimportant on the web.
Scenes often comprise gigabytes of lossless webp, some of which you can see at https://superspl.at.
‘The average Web consumer’ may not need lossless, but a non-negligible minority very well might, hence why lossless should absolutely be on topic.
JPEG XL is an open format with a libre reference implementation, usually compresses better than WebP/PNG, and supposedly has plenty of room for improvement still (in said implementation). Add to that its versatility in other areas and the fact that it seems to have generated widespread interest (much unlike WebP in its time, from what I recall), and I think campaigning for it makes perfect sense.