Usually, you use the display to represent stuff that's in the memory of the controller, either directly or indirectly. Doing a backspace on the display in my opinion is a sign of questionnable software design. Because doing a backspace on the display is asynchronous to what's happening in the memory of your controller. It depends on what you are trying to build of course, but if it isn't for displaying for displaying's sake (an exercise in using the display), it seems like a function you'd better avoid.
Tell us what you are trying to build?