Because it allows for proper prioritization of needs, allows for the better exploitation of our surroundings (as tool using animals), and is INCREDIBLY useful for helping us try to “model” other human’s behaviors and act as social animals as opposed to just being the regular kind.
Probably the most impact “Why” question probably started occurring before we were even human and it was “Why did they do that?”
Being able to understand the motivations of other beings is absolutely fucking incredibly overpowered both in terms of cooperative action with your fellows AND destructive action against foes/food sources.
Historical legacy. It made sense when they were first rolling out. Someone would take the risk of trying to build up a market for these really expensive new devices and then the factory would swoop in and undercut them and destroy their business after they had done all the initial leg work of creating demand for the vehicles. They wanted protection from this.
Well, cars are now everywhere in the US market and it doesn’t take a whole lot of effort anymore to convince someone they need a car, and not just a horse. But the laws protecting “car market development” in the former of dealerships never went away.