Oh absolutely, but if I were targeting Zuckerberg this would now be a camera he carries with him and almost always has an available network connection (If I were a billionaire I'd be switching devices near constantly to stave off attacks). You could be carrying around the bug for at least a year if not more.
Your average blackmailer would be better off with the separate camera route (and likely wouldn't be sophisticated enough otherwise) but a state-sponsored attack could probably pull it off.
Not really - there are lots of times when you will not be present with your laptop (think airport security).
It's orders of magnitude easier to get access to a mobile device than to setup a camera in every possible location a target might move to. But they'll helpfully carry the device with them.
If the attacker has done this, they might as well just hide the camera somewhere else.