It's so easy to see this coming: you buy a new car, and you own an iPhone (probably a future iPhone, with some additional hardware). You download the Carkey application from the Apple app store. The car dealer gives you the code for your car, and you program that into the Carkey app. Now you can unlock and start your car from your iPhone, you don't need to buy an expensive metal “smart” key for your car. And as usual, this feature comes to Apple first; all the other phone manufacturers eat their hearts out for a year or two, before they are allowed to offer the Carkey app for their own phones.
Why not? This is just routine computer convergence.
Oops, I better call AAA; my iPhone needs a recharge.