The surveillance system gives you the footage. If police can't do anything with it, that's unfortunate, but not the fault of the surveillance system.
In this instance I'd say the surety and closure provided by the ability to simply review the footage is an important aspect for potential victims. And if victimized by something worse than petty theft, the value only goes up.
I’m not saying it’s the fault of the surveillance system if police don’t use it. But what is the actual benefit to you/society as a whole we film our neighbours never completely trusting them, if the people paid to protect others aren’t using it.
Seems superfluous if police don’t use it when provided to them voluntarily.