You stopped carrying keys around because that's a choice you made. But that still doesn't mean it's a problem. Using a physical key takes literally seconds to unlock a car. And failing that, wireless keys have been a thing for a long, long time and are actually faster than using a phone.
So again, this is one of those progress-for-the-sake-of-progress things that the world just didn't need. It's more for the people making the money off the phones and the cars than it is for you or me, or to solve some sort of real-world problem.