And yes, you can find this out just by physically following someone wherever they go, but since that's impractical to do on a mass scale, it's not likely to be done for people who aren't targets of specific criminal investigations. License plate scanning collects this personal information indiscriminately about totally innocent people.
And this information is likely to be abused by people in positions of power, just like existing records about people are. I can't count how many times have I've heard about cops getting in trouble for running unauthorized database searches on ex-girlfriends, etc. Detailed data about a person's every movement would be even more tempting to abuse.