This response won't make me popular but mainly laziness. Most fellow sailboaters that see me back into my slip come up and ask me how I can do that so easily. When I tell them I practice, they become disinterested. There is no real magic trick [other than typically they are not giving it enough throttle]. Go find an empty mooring
and practice backing up to it. Learn how to back your boat up and how it handles.
The legit reason I have heard is privacy. If you are bow in then your cockpit
is to the water
and people can't see down the companionway
. I get that some times but it's not really a factor to me due to the setup at my dock
but it is something we consider at transient locations. Usually the ease of getting on and off the boat with the walk through transom outweighs most of the other thoughts and we end up stern in.
It's also a skill that served me well when on a charter
in the BVIs and the transmission
broke. It wouldn't go into forward but would go into reverse. I simply reversed us into a morning when we couldn't sail into it due to low wind
in the lee of Marina Cay.