It looks impressive from far away, true, but that's not really voxels, at least not in a useful way. It's creating cubes to simulate voxels and using the hardware to draw some number of those cubes. Once you zoom in it starts to become a less impressive demo.
I should be able to send "sphere" to an engine and it will render me a sphere, no matter how close I zoom in it will always look smooth. Then send a bunch more primitives, manipulated to look like trees, and zoom in on those getting tighter and tighter detail as I go, then a bird on the tree and a feather on the bird and a bug on the feather and the green grass grew all around all around. And at that detail it doesn't look like a sphere anymore, for it has ridges all across it. Just more and more detail all handled by the hardware.
Of course, you also need to train an entirely new generation of artists. Working with voxels is distinctly different from working with meshes. I'm quite convinced that we're pushing the bounds of geometry now, there's only so many more triangles you can add before it becomes completely pointless, and a paradigm shift is required, but using primitives to simulate voxels (a technique that has been used by many games already, make no mistake) is really only a first step.