If we take the perspective of the student then clearly there is no right or wrong, just "did I learn or not". There is more than one means to achieve an end, and the different 'personal' touches have always been what makes your lesson enjoyable for the student.
All that being said, IMHO the answer is "no". I would think that the only time it makes sense to omit teaching a switch cast would be in the case when the student(s) have already learned it thoroughly.
Both the circle and double mentioned require a sound knowledge of the switch cast because once the lift and setup are complete there is nothing left to do but come around and make a switch cast.
If you started with only a roll and proceeded to a snap/C/double then you run the risk of having the student attempt the cast with incomplete rotation and momentum to form a proper d-loop
- small D-loop unable to load the rod
- lack of momentum == "bloody L"
- anchor too big to lift
- incomplete understanding of basics