From what I gathered by watching Taryll's video, there is no way to refit these engines with a regular carburetor because they have no internal governor. Everything is controlled by electric stepper motors, a temp sensor and an RPM sensor.
I think someone at Cub Cadet division forgot to tell the upper management that these are still mowers that have to operate in extreme conditions. Kind of like why do they put a cup holder on a rider? Dirt, dust and clippings will attract to any sweating beverage container around the general area. (This had to be an office idiot and a crafty salesperson dream).
At the moment, I just do not see a future of any kind for this design.
It makes me wonder what happens if someone eventually attempts to install a totally different (conventional) engine, it will certainly mean a wiring harness and operator cables at a minimum.