My two takes on the single minded focus on plate number records are as follow.

The cynic in me says it "is" about the LPR because the, roughly speaking, white collar middle class white people who suddenly now seem to care mostly drive new enough stuff to not be piled on with bumper stickers, have color mismatch, dings, etc, etc. and they care only so far as it effects them and they don't want to completely not track the poors and their sketchy vehicles.

The non-cynic in me says that breaking the information chain is good enough. Knowing a silver Camry has been coming and going and where doesn't really mean anything. It's being able to automatically tie that, via a plate number and corresponding records, back to a person. If someone at a later time decides the care can go looking, but it renders much harder a lot of bullshit "find me everyone who's too rich to be driving through Kensington because they're probably there for drugs" fishing from behind a keyboard expeditions, which is a huge plus.