[Terr_]

There may be a blurring of use-cases here, between:

1. Starting a car from a short distance in order to pre-heat in cold temperatures or because you're in a huge hurry. (Or paranoid of car-bombs, I guess.)

2. Starting a car from a long distance on someone else's behalf so that they can borrow it for some reason.

While I think #1 is most common, #2 overlaps with other "call support to unlock your car" or "disable if stolen"-type features. So it's likely manufacturers are motivated to use cellular connections "because it's already probably there for the other stuff."

P.S.: That said I really don't like the lack of owner control implied but some of those systems.