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.
Visibility. When you back in you have full awareness of your surroundings.
When you back out there’s a gap of time between getting in your car and backing out (opening the door, starting the car, seatbelt, adjusting radio, etc…). If you have cars parked on either side of you, you won’t be able to see the cars driving past you.
Then there’s efficiency. If you get a call while you’re in wherever and have to go somewhere quickly, it’s faster to have your car pointed in the right direction.
Situational awareness is what I use to sum it up. You have it coming in, but not going out.