It would matter because sleeping in a moving car in traffic in the middle of a city sucks in comparison to sleeping in a parked car in a quiet street on the out

It would matter because sleeping in a moving car in traffic in the middle of a city sucks in comparison to sleeping in a parked car in a quiet street on the outskirts, and also uses more fuel and wears out the car faster. There's no gain to driving around in circles while sleeping compared to having your car go and park somewhere.