BMW - the car unlocks the doors when I approach and auto locks the doors when I move away from the car, so generally I never interact with 'locking' at all. Except when this doesn't work, for instance, if the boot is open because I'm getting shopping out, then I close the boot and walk away, quite often it will not lock at that point, perhaps because I moved away from the door but it didn't lock because the boot was open. The app is useful so that I can firstly check the car is locked, and secondly lock it. I personally have no need to unlock remotely - maybe my wife might say 'hey I need to get something from your car' and I'm not around? But I've never needed that yet. My wife's Hyundai has told me via the app 'hey you've left the car unlocked' and I've been able to lock it remotely. So definitely in favour of that feature.