They didn’t need the car in the shot. JMHO
Maybe they included the car for perspective, so that you can tell that the stars are really, really far away. Typical European-type license plate (wider than the US type).
I guess an accomplice, if there was one, could have driven the car out of sight for the shot. Probably the shot was taken by a person working alone.
On another level, this would make a good car advertisement if you could make out the car brand.