I have one and don't mind at all. My insurance company is also my health-insurance provider and would know immediately if I have an accident, so they'd call me and if no answer would send help automatically. If my car is stolen, they can track it. They have a clause that prevents them from using the data against me in e.g. an accident claim. I get up to 50% of my fuel cost back monthly if I drive well and e.g. check my tire condition yearly (although linked to household insurance as well). I have friends with fast cars that wouldn't touch this and that's fine - keeps my premiums down because I'm not subsidizing their behavior.

I'd rather have them tracking me than my Android device, say:

https://www.google.com/maps/timeline