> In reality while using a webcam the other end of the conversation is probably looking at a highly compressed video image in a small window
I dunno - all those extra pixels make a big difference when staring at a panel which is about the size of a Royal Mail commemorative stamp!
Especially when the person at the other end has applied some background masking filter to disguise what they've got sat on the bookshelves behind them ;)
Admittedly, there's something potentially to be said for having more pixels - it gives the system more to work with when applying denoise and resampling filters. OTOH, both cameras probably have the same physically-sized CCD, which means that each individual sensor is smaller and therefore receives less light, so it's a choice of quantity vs quality...
Also, and entirely anecdotally, I've heard that at least one big company in the area has given up on using video conferencing altogether, as their increasingly creaking VPN just doesn't have the bandwidth for it!