People are going to be breaking into your car to steal stuff 99% of the time, not trying to steal the car itself. They are often homeless, or have some sort of chemical dependency, or are mentally ill. They are not going to have the foresight, funds, or ingenuity to use some sort of electronic hacking device. They are not going to make the effort to scout out people as they leave their cars (of only certain makes and models) and play secret agent to use some sort of device between the owner and the car. And they break windows in broad daylight all the time - just smash, grab, and run. It's not like anyone is going to try to tackle a meth head running away with some stranger's $90 GPS.

Even on the infinitesimal chance they steal the car itself, you have car insurance. It doesn't really matter aside from the inconvenience, and the odds are so low it seems like a silly thing to be an absolute deal breaker for anyone.