Surveillance case studies in urban environment have shown to decrease crime rates and more importantly violent crimes. Under the proper circumstances this type of citywide surveillance can be a benefit to modern societies.
Even so, the question is larger than that - a) how well does it work (i.e. would the money be better spent on traditional policing) and b) is it worth what we are giving up (the ability to go about your business without being monitored, tracked, etc.)?