I agree with your points of it not being worth it for most people and fixing lighting is a big factor -- however, even on zoom calls, using a proper camera / lens combo is very much noticeable compared to a regular webcam, regardless of the compression.

I've run a a6500/sigma 30 f/1.4 combo for a couple of months just for fun when COVID started and everyone noticed the quality difference. I ditched it in the end because it was way less convenient then to have a single usb webcam and nobody gives a shit about how you look.