this article in particular was an interesting case for the benefits of ALPRs: https://www.worksinprogress.news/p/a-cops-case-for-flock
tl;dr - actually useful for stopping car related crime like thefts, which has a wide ranging affect on other related violent crime, - is not the same as facial recognition, or phone tracking - abuse is detectable - constitutional arguments for ALPRs being a form of privacy intrusion are flimsy since they are mostly applied to public roads which have no privacy protections