Interesting idea but...
When you start looking into how neuromechanical control works you realise there's a lot more to it than the brain, muscles and some wiring in between.
A lot of muscular control and sensory feedback handling is embedded in central pattern generators in the spinal cord. Lots of autonomous actions and interactions that don't even need input from up top. Stuff like leg and foot motion, motor response and gait is driven by this layer not the brain.
So hopefully they've put their work into detecting intent and built the fine control and feedback into the hardware itself, because that's how the original systems work.