Most might agree, but you still need it to work without a phone with good interface and all the desired features. Still not everybody has a smartphone. Or you

Most might agree, but you still need it to work without a phone with good interface and all the desired features. Still not everybody has a smartphone. Or you have an older one and whatever software you need for the car isn't supported. Or you give the phone to the kid in the backseat to play a game... And then having two very different ways to control stuff increases complexity. For developers and user.