It would be a hassle every single time I wanted to drive. Entry/exit is a fundamental part of driving, and it does this poorly. There was a Model 3 review video linked here the other day by a couple after 6 months of ownership. They were extremely positive about almost everything except the "frickin' keycard," which was driving them crazy with frustration. I think they said something like "Tesla is going to have to fix this!" Also, a prevailing thought on the forums has been that if you don't love the phone-as-key, then you're a Luddite or too old or too last-century, that the car isn't made for you, and you should go somewhere else. I'm taking that advice.