I'll continue the OP's strange nomenclature for clarity's sake.
"back parking" is the recommended way to park into that type of space.
"front parking" is more dangerous because when exiting the parking space into the road, your visibility is restricted. In particular, small children and other obstacles could be missed - especially in busy lots like supermarkets, etc.
By "back parking" you only drive with restricted visibility the short distance from teh road into an empty bay (which you have already verified to be empty and free of obstructions by driving past it). As the bay is not a road, it is less likely to acquire an obstruction (such as a child or shopping cart) in the time it takes you to reverse in.
There may be other restrictions which require you to "back park". E.g. it is illegal to reverse a car out of a driveway and onto a public road in some areas. Unless you have space in the driveway to turn the car around, the only legal option is to "back park".