I've had BMW 530e that had the Car Key. Compared to the Tesla, it was much worse user experience. If I want to skip carrying my gigantic car key, every time when I open the door or start the car, I have to bring up the Car Key and place it right at the handle or under the infotainment system. Well, the Car Key slot under the infotainment system isn't big enough to fit the iPhone 16 Pro Max, so I have to awkwardly put the phone in there so that the NFC is close enough to be recognized.
That versus Tesla that just recognize my bluetooth is near and unlock and start the car. Hey, I don't even need my phone because it also recognize my Apple Watch is near. There have been several instances where I could open/start my Tesla with my watch when I couldn't get my phone.
I can technically start the car with my Apple Watch using Car Key, but that means I have to take my watch off my wrist and place it above the NFC slot awkwardly. I ended up just using the normal gigantic key for BMW.