Ah, that's an interesting point. I haven't tried to correlate that, but it must be true. For example, the screensaver never seems to appear during Zoom calls!

That might also be implemented as "don't start the screensaver if the camera is in use". Easy to detect in either /proc/ or /sys/, I forget which one I was fiddling with.

Nah, I know people who use Zoom for this purpose without the camera enabled. It's just Zoom invoking the OS's wake lock.