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.
I’m always in heavy traffic but also almost always parking at a meter, so there’s a measured amount of space. So I’ve started doing “forward parallel parking.” As soon as my front wheel clears the first car, I turn hard towards the curb at the center of the space. Keeping an eye so I don’t scrape their bumper, I roll forward 2-3 feet, then turn enough left that I’m aiming at the center of the bumper of the front car. I roll forward as far as is safe. Now, I’m probably not in quite far enough to just roll straight back, but I’m parallel to the curb and out of traffic enough that people can get around me while I back up more towards the curb, straighten out and roll forward into the center of the spot. And if I weren’t driving a minivan I could probably be all the way in already.