Overall, JPEG XL addresses many of JPEG’s shortcomings. The 30-year-old format is not very efficient, only offers eight-bit color depth, doesn’t support HDR, doesn’t do alpha transparency, doesn’t support animations, doesn’t support multiple layers, includes compression artifacts, and exhibits banding and visual noise. JPEG XL tackles these issues, and unlike WebP and AVIF formats, which each have some noteworthy benefits too, JPEG XL has been built from the ground up with still images in mind.

Source: Why Apple uses JPEG XL in the iPhone 16 and what it means for your photos - OSnews

Sounds leagues better than HEIF