Your vehicle is a precision piece of hardware. It has moving parts that move thousands of times per minute. It's a smooth-running, awesome machine. As such, it needs care and maintenance to keep up its standards of performance. That's where you and your dealer come in. Your dealer has professionally trained technicians that know your car, and what parts and maintenance your new car needs. Even though your new car might be brand new, it still needs check-ups to maintain the versatility and integrity of this special machine.
You've likely heard of synthetic oil, and quickly dismissed it, like a lot of people do, as simply an artificial oil that might hurt your car. Actually, synthetic oil is slightly misnamed. Although it is synthetic, it's actually natural oil that has been processed at the molecular level to operate and remain viscous at higher and lower temperatures than natural, conventional oil.
When your engine heats up, the oil surrounding the moving parts has a tendency to break down, and the additives in the oil --- the detergents --- break down as well, leaving your engine dirty.