With beginners no, because the switch cast provides the beginner with the basics of the spey cast in an easily practiced and repititive manner. Thus, allowing a person new to spey casting an opportunity to learn the basics of D Loop formation, anchor, and forward spey.
With folks who have been spey casting before, I would skip the switch cast for the simply reason that even if they don't have good energized D Loops, the know about them and the need for proper anchor placement. Therefore, the switch cast is not the most useful or efficient way to help those who have been spey casting improve their casting. They need to learn how to get a good, energized D Loop and well formed forward spey loop with the casts they are using when fishing.