2. Bluetooth is pure crap, the UX for connecting and managing temporary devices is absolutely insane on all devices. This is something you do on your own car but is a major hassle to setup for temporary occasions. And hardly something that is done on a whim just to demo something. It is just that bad.

And this is even before considering compatibility issues and security issues, of which there are plentiful. And cars also have this habit of trying to harvest all your contacts etc. (Wonder how many contacts are floating around in rental cars... sigh)