Lossless transcoding is not a selling point IMO. It’s not relevant for new images (new devices aren’t producing jpegs), and I just don’t see people mass re-enco

Lossless transcoding is not a selling point IMO. It’s not relevant for new images (new devices aren’t producing jpegs), and I just don’t see people mass re-encoding their photo libraries. Features that actually matter to normal users are what is important. In that area progressive display seems like it would arguably be more useful, though I think it would still be dependent on what the image size is - websites now routinely require megs of JS to display anything at all, because net speeds are now fast enough that huge amounts of data are needed to get to a “noticeable” latency that would warrant display of incomplete data.