The thing that I like the best about jxl is how consistent the reference encoder is. If I need to compress an entire directory of images, cxjl -d 1.0 will generate good looking images at a pretty darn small size.

Using mozjpeg (SPEG), or openjpeg (JPEG 2000) or cwebp, and I want to get even close (in bpp) to what cjxl does on the default I have to use different settings for b&w vs color and line-art vs photos.