If nobody could see your car, would you still want the exact same vehicle sitting in your driveway? That question can expose something surprisingly useful about a car purchase: whether the buyer wants the machine itself or the message that comes with it.
Cars do practical jobs, but they also carry social baggage. A luxury badge can suggest success. A giant SUV can project capability. A spotless sports car can announce that someone has decided errands deserve better scenery. None of that makes a purchase foolish. It does mean buyers sometimes pay a lot for things that have little to do with transportation.