Why were those installed in the first place?
Harvest data and let the techno fascist state that is slowly emerging figure out a use case later. For potential scenarios: if you like sci fi you can watch minority report, if you like history you can look at central Europe around 1930
Speaking only for areas near where I live, it was in response to a persistent uptick in home invasions. Police can't be everywhere at once, and LPR cameras flag stolen cars and mismatched plates that thieves like to use.