The term for this is "transparency." A codec is "transparent" if people can't tell the difference between the original and the compressed version.
So it would be `transparent lossy compression`? To this layman `perceptually lossless` sounds more clear, but i understand the issue with the name.
I work in graphics. Calling this transparency would be a terrible idea and make a lot of discussions around compression of videos and images with actual transparency very confusing.
Does the compression algorithm work well for transparency? Yes, it's effect on transparency is totally transparent! In fact the transparency is fully transparently compressed by our codec.
Yeah, don't do this please. Perceptually lossless is a term I've heard lots of times before and companies developing codecs usually have a fairly strong technical basis for making the claim. As in, it's not like they just glance at the results and say "yep, looks good to me". Rather, they'll be looking and spectral curves and image diffs - probably also motion diffs for videos - and checking whether they the losses are small enough to be undetectable to human eyes.
"Transparency" is a fairly annoying term for this in image/video because of the obvious polysemy.