Dual extruder printing using soluble support material is about to become mainstream.
However not only are scaffold materials expensive, using them massively increases print time and complexity.
A great solution is to have the majority of the support is printed using the primary extruder / model filament and only the "interface layers" between the support tower and the model are printed using specialist scaffold material coming from the second extruder.
Hope we can have it in the big update!