Please correct me if I'm wrong.
Taking backsight observation is a process of aligning your horizontal circle. This is to make sure of the coordinate system consistency in the entire project.
I guess that there is a unique case that you don't need to perform backsight observation for as long as you're very sure of backsight point information. Setting up fresh a total station is having its horizontal circle not correctly oriented. Horizontal angle difference or angle correction can be derived between correct orientation based on stored coordinates and disoriented horizontal circle reading. The correction value can be applied to all subsequent observations. In this case, no backsight observation is practically needed. This means that if a total station supports this, a great deal of work is eliminated.