You can do a very similar thing in virtual reality with TiltBrush. You don't get a physical object at the end but you do have a lot more flexibility in the structure and appearance, and, of course, the magical power of the undo button. And maybe you could get a physical object out with the help of a 3D printer...
I believe 3D sketching and CAD will be the first popular non-game application of virtual reality. 3D CAD with 2D I/O (mouse and flat monitor) has always been a little too difficult for the masses. Virtual reality with natively 3D input and output makes 3D CAD an order of magnitude easier and more fun. It could give a real boost to the 3D printing market too, as once the masses start doing CAD they're definitely going to want to print their creations.