At the state level, there are some states that have already implemented facial recognition. I can tell you that even at the state level, integration was not easy. At a federal level, IAFIS is not limited by capability, but by sheer size of the database and the number of requests -- this only for fingerprint packets (I don't remember if they process palm data, but palm data definitely increases packet size significantly).

The point is, sometimes we are mesmerized by prototypes and applications at a small scale, but when you increase the scale, development, integration, and deployment challenges (edit: and costs) increase exponentially.

They do on CSI all the time!