Here in Maine shooting while moving both forward and backwards is part of the LEO qualification courses.
We train on moving and shooting quite a bit, you never know when you might be clearing a room or advancing on someone and need to fire, or need to move to cover while firing. A little familiarity can go a long way towards putting rounds on target and it's always better to be accurate than not.
"If violent crime is to be curbed, it is only the intended victim who can do it. The felon does not fear the police, and he fears neither judge or jury. Therefore what he must be taught to fear is his victim." - LtCol Jeff Cooper