With a webcam, performance would unavoidably vary a lot between customers too due to the dizzyingly wide selection of webcams in use, all with differing perform

With a webcam, performance would unavoidably vary a lot between customers too due to the dizzyingly wide selection of webcams in use, all with differing performance characteristics. They'd have to contend with everything from USB webcams from 2002 up through the latest 4k webcams, not to mention image processing quirks those often come with like face smoothing.