Whether or not cameras will deter thieves, they are a good idea, IMHO.
We have 8 cameras, some not so obvious.
We have every entry point alarmed and backed up with motion sensors, some photo beam, too. I made bars for my garage windows. Its on the ground floor and they look like ornate grills, not ghetto.
There is a sensor for driveway entry, as well as a motion which turns on all exterior lighting. This helps extend camera range and resolution, at night, as well as deter.
Then the 4 motion sensors around the property.
The alarm and camera "brains" are in a room which has a reinforced door. They have a dedicated battery backup, very extended supply, and a cellular communicator. The signal is sent to mine and my wife's cell phones. If we don't respond to it within 120 seconds, via text, it is sent directly to 911. Good thing we live in a small town, I got to know the operator pretty good when I was installing
The camera system can be viewed on any TV in the house by simply switching inputs.
Overkill, I think so, but we live outside of town, on a quiet road and, oh yeah, my wife wanted it......
I got most of it from HomeSecurityStore.com and the rest from wholesale vendors.
I installed everything myself, didn't take an afternoon, but thats where the savings come from.
As for you ball pit, is it something like this