This is indeed one of "good reasons" that can prefer AVIF over JPEG XL (but not a good reason to not ship JPEG XL). Safari is the most difficult vendor to work

This is indeed one of "good reasons" that can prefer AVIF over JPEG XL (but not a good reason to not ship JPEG XL). Safari is the most difficult vendor to work with, so if Safari can be convinced there is no bigger obstacle waiting. But it should be noted that Safari still does not support AV1 on which AVIF is based and that fact didn't prevent other browsers from adding support for that video format anyway.