One of my local ranges has one, and they even have a class that allows you to use it. I played around with it in my Defensive Handgun Class. It mostly has LEO scenarios. But it did have about 3 dozen civilian scenarios, each of which had 2 or 3 different ways (usually the BG would fight, run, or surrender) of playing out depending on how the instructor decided to run it. So in reality there were about 100 different scenarios that could be run on it for civilians. You weren't rewarded for acting like a hero, and as a matter of fact, more points if you could avoid a fight. It was actually quite eye opening because it put you in certain positions you might never have thought about before.
I wish I could remember the brand name. The instructor was saying that if you had a projector, screen and computer, the basic setup could be purchased for less than $1000 (included software, the light gun, and the camera that "captured" the shots).
I find them unrealistic and far too naive and simple, if for no other reason than the "bad guy" responds the same way each and every time, no matter what you do. It doesn't react, respond and adapt to your actions, and there's no sense of continuum. I found it to be simply a computerized version of the old good shoot/bad shoot walk and pop simulations they used to use in the old days ala Magnum Force.
You were using an old one then. The one I played with allowed the instructor to change what was going to happen on the fly. Sometimes the BG would surrender as soon as your gun cleared leather. Other times he would run, or fight back. There were several times during most scenarios when the scenario could be changed. So even if you ran the same scenario, it wouldn't always play out the same way. Even running the same simulation file, you had to be on your toes because the BG might react differently...and there may even be a different person who is actually the BG.
I agree it's not perfect. But there's absolutely no training out there that can fully prepare you for an actual use of force scenario. But this kind of training, along with other types of live fire can certainly make you better. Saying their naive and simple would be like saying shooting at a target on a square range is too simple and ineffective. By itself, yes, it's ineffective. As part of a well rounded training regiment? Both of these activities will be helpful.