I use CAD on a daily basis and I can't think of how this would improve my productivity.
As others have mentioned, this might be a great review tool, but i wouldn't actually create anything with this.
As per the being able to spin/pan/zoom a model using hands, i can do all of that, with very good precision and intuitive feel using a spaceball from connexion in my left hand (which isn't even my preferred hand) and leave the right hand available for a three button mouse.
I have great respect for Musk, but both this interface (at least in this form) and 3D printing are nothing new/revolutionary nor synergistic as he'd make you believe.
now, i am curious about CATIA's Natural Sketch
http://www.youtube.com/watch?v=66FoxykeT0w
which could be great for the very beginnings of conceptual design to get the rough shape right. Anything requiring details would probably still require the good ol' 2D sketch using a mouse.
I think it'd be cool to have the electronic equivalent of a drafting table, with a touch sensitive big-ass screen replacing the paper and the ability to produce 3D shapes using Natural sketch or something similar. If I could use a light pen to sketch a circle where I want it - instead of using a mouse to click the plane, click the icon for a circle, then click the center, then click the radius, then click accept, and switch to the next command - then i could really start saving some time. I'm talking a 2x factor at least.