If introduced, even for just crime, facial recognition software can become more widely spread as using it for "targeting criminals" is a stepping stone towards introducing it into wider society.
facial recognition data allows people in a high position of power to keep tabs on people and their personal, private information. they could then use this to take advantage of the vulnerability of people beneath them while going unpunished
If you don’t commit any crimes or have anything to be worried about from about from a legal perspective then what’s the problem with having facial recognition? Should have nothing to hide or worry about.