It’s safer to back into a spot when parking than to back out. When you back in, you’ve just seen the spot and any obstacles while going forward, so you know what’s there, even if you can’t see it when backing in. When pulling out backwards, enough time has passed that any number of obstacles can have appeared, so you need to be able to see every obstacle in your way, which is much harder backing out.
It’s safer to back into a spot when parking than to back out. When you back in, you’ve just seen the spot and any obstacles while going forward, so you know what’s there, even if you can’t see it when backing in. When pulling out backwards, enough time has passed that any number of obstacles can have appeared, so you need to be able to see every obstacle in your way, which is much harder backing out.