I camera can't stop anything. Just like laws don't stop anything. Keep in mind that with stopping I mean: blocking an action from being taken. So if I want to d

I camera can't stop anything. Just like laws don't stop anything. Keep in mind that with stopping I mean: blocking an action from being taken. So if I want to deliver a bag of meth to your doorstep, even if you have 99999 cameras on the wall, that bag is not going to be prevented from getting dropped off. Same goes with dropping pipe bombs, stealing packages or breaking in to your car which might also be parked in a place a camera can see. All it can do (like I wrote, and like you wrote) is act like a deterrent, and, after the fact, when the action has already been taken, be used in follow-up activities. Now, granted, some people walk around with a mindset of "If I can get away with it I might do it" and then a camera can be enough of a deterrent, but if we're talking about safety, we're not talking about a subset of potential bad actors. People who are not thinking about consequences or are desperate enough to not care will not be deterred at all by a camera, and some of them might realise that if there are 10000 crimes, small crimes might get less attention than big crimes. Cameras are mostly useful for when you want to do realtime communication, or when you want to see something after the fact. Oh, and for spying, of course, but that sits nicely under the 'realtime' umbrella.