Just an observation: The “square/right-angle” parking spaces are harder to park in, but do make it easier to pull-out/exit in either direction. The angled spots are easier to enter/exit, but it’s harder to exit in one direction than the other.
This might be desirable in order to influence cars to enter/exit in one direction.
In the common US box store layout, the end of the parking lot nearest the store is often highest in pedestrians. I find it easier/faster/safer to avoid that end of the parking lot. So I try to enter/exit using the side of the parking lot opposite the store. Angled parking slots make this strategy harder.
Undoubtably there are more factors than this involved in parking-lot design.