There are useful things about internet connections and phone home. Maybe not for you, but for many.
For company vehicles when the car is due for an oil change the mechanics should be informed not the driver. Likewise the company should be able to track where their cars are and when they are driving (and restrict them from driving outside of their territory). For things like snow plows the company needs to track where they have plowed already.
When it is cold it is nice to tell the car to start warming up 5 minutes before you get into it. For electric cars that are currently plugged in this is important as it lets you spend grid energy to warm up the car instead of range.
It is also useful to have up to date maps on the car - there are things a built in system can do that android auto / apple carplay cannot do. Though you have to drive a lot for this to be worth it. (My car as GM's onstar and no android auto - I don't pay for it, but I could see in a 10 minute test drive how onstar is better if you are driving the car for hours every day - since I mostly work from home or bike it isn't worth it, but I can see how it is better despite not being better)
But there needs to be a non-charge option for things like remote start.
All spying needs to be owned by the person who owns the car. GM or however might have data, but it needs to not be accessible by them except by my agreement. Do I want my dealer to know when I need an oil change - maybe (depends on if I trust my dealer), or maybe I want my independent mechanic to know this, or maybe I change my own oil and want only me to know.