One problem with this design is that the light would deflect off the center particle and melt other sand around it. In the video, pretty much everything in 1cm radius gets melted. Unless he can somehow make it print in greater details, I can't think of a better use for this other than producing planting pots.
This technology could be used to make water sills and collectors in the desert. If you spend a week out there making water collectors, a couple weeks later you may find you have enough water for a village or two.
Glass-forming in the desert could be the basis of an extraordinary micro-permaculture effort to build oases and gardens in otherwise impossibly hostile environments.
This, plus a lot of water harvesting, could solve a lot of very difficult problems.
If SunCutters can be made to make more SunCutters, and if templates for the SunCutter can be easily made, then I say once this tech is available to the desert masses, it could very much revolutionize restoration of these difficult lands.
The machine needs to be scaled and cheapened - but it MUST be made to make bricks - over time, the bricks will be refined and they will be available for sale in the Organic or Fair Trade aisle of Home Depot.
A smaller version shall be made and refined to allow girls in west africa to make beads and cups and such.
I think there are lots of uses for coarse-scale 3-D printing of fused quartz. (Did he mix in any lime to lower the melting point, or is that more or less pure quartz sand?) Furniture, coarse parts of machinery, sculpture, buildings, and the like.