Worth mentioning: their demo only uses two passes for progressive AVIF -- it's just their choice. You can have up to two more intermediate passes, so at 30% you can have something much closer to the original image.
Even still, the demo proves that AVIF can deliver a usable image with up to 3x as fewer bytes as JXL!
Even still, the demo proves that AVIF can deliver a usable image with up to 3x as fewer bytes as JXL!