Show me any of the popular image conversion tools (avifenc, imagemagick, photoshop, ffmpeg, whatever...) that does the identity matrix hack when asking for lossless AVIF. None of them do it. Many people have been burned by "lossless" AVIF, where they converted their images in the mistaken belief that the result will be bit-identical to the original, only to find out that this wasn't the case, after they've deleted the original files.