You're making a false comparision between none and many when it seems like a few would be a much nicer place to live after accounting for civil offenses and the points made by parent.
This technology puts a human face to technological surveillance, there has to be some minimum psychological cost for everyone there which may outweigh the claimed benefits.
Do we even know what an "outstanding warrant" consists of in China? Granted, I may be naieve about what it represents in the US, but I hope it's something that comes from a reasonably transparent and fair process. In a totalitarian state, it could mean something else.
The question becomes: Who is being rounded up, and why? This seems more important than the specific technology used.
I happen to live in a neighborhood where the very presence of a police officer would attract notice.