24 megapixel almost-lossless photos dumped straight from the camera are too heavy to be used directly on the Web. They also have lots of metadata including GPS location, that people usually don't want to share.

In practice you'd want to resize it (HD is 2mpx, and 4K resolution is 8mpx), and recompress to quality suitable for viewing not editing (makes huge difference in file size).

The necessary recompression step makes the input format mostly irrelevant. The upside is that JPEG XL is free to use, so it's possible to legally write tooling using it without touching the mess of H.265 patents.

They might reconsider.

https://www.phoronix.com/news/Chrome-JPEG-XL-Seconds