It’s perfect for all parties, and doesn’t intrude on your personal living space or devices.
Well that level of intrusiveness would just make me come up with something overly complicated just so I could prove that I could cheat if I wanted.
That's why they make you share your screen; obviously there's plenty of ways to fool that but the goal is to make it so that cheating requires enough effort to where it's probably less effort just to study and do it right.
They just want to make it difficult enough to catch most.