You'd be surprised from people with a bad sense of direction. It can also be handy to initially orient yourself in the context of something like a maze.A rotating map doesnt even make sense, i dont remember using a real map, but i guess it would be stupid to keep rotating the map everytime you turn just to keep your goal point in front of you.
Some people's brain's just don't handled left and right turns in terms of cardinal directions though. My wife couldn't navigate by general directions in real life at all much less a videogame that's much more dense and complicated than our rural area.