These voice control schemes almost always end up as a cool gimmick, and rarely as a productivity boosting solution.
For example, I could go to tend garden and yet think about some problem, take notes, even code. Or check email, browse internet. I can work on hardware thing and have schematics or specifications appear in front of my eyes. I can have a walk and take notes. I can eat while working.
Eventually, no office will be required. You can just stroll in the park and get the work done.