Visibility is way better and traffic rules play to your favor.
When you back in, you already have right of way. Traffic has to wait for you to park and you aren’t reversing into cross traffic.
If you park forward, when you go to leave you have to worry about cross traffic and your head/eyes are far removed from where you need to be looking. You don’t have right of way which means a lot of awkward mashing the brakes when a car or pedestrian pops out of your blind spot.
In short, you can park faster and more accurately and you can leave faster and safer.
The only reason to park forward is there’s a line of cars behind you that won’t let you reverse into a spot. Otherwise, it’s always the right choice.