To me, it seems objectively easier to pull into a parking space forward and then back out of the space when you are ready to leave. You don’t have to line up with the lines while driving backwards, and it’s easier to keep from hitting other cars as well. So why back in? To me, the only advantage I can think of is that you can get out quicker, technically.
Edit: I do not need driving instruction, just wondered why. The reasoning.
The sun is directly towards my window shield, if I back in. I can put a Sun visor in the windshield and the car is much more tolerable temperature-wise in the summer. But only if I back into my parking spot.