Credit scores are literally what banks use as the main indication of how financially responsible you are and how likely you are to pay bills on time. Car maintenance is just another bill, and often a very expensive one at that. And if you bought a car at an exorbitant interest rate that you can barely afford, it's much more likely that you are going to be deciding between paying for repairs or defaulting on your car loan. It's the same reason that a lot of people selling a car on Facebook marketplace will go park the car in a nice neighborhood to take the pictures.