I kind of wonder what problem this would be solving? It sounds magnificently cool, but also expensive. In the long run, I have great hope for fiber lasers becoming cheap enough for a home-version. Maybe a home-grade 1kw. Seems more practical than worrying about recycling sand.
I do love the idea of a Rail gun cutter, though - just not sure how it could really help cut things.
I'm thinking in terms of resource-constrained use cases, like on an aircraft carrier or further out, deep space exploration. Until this thread, I had always assumed a laser cutter would be just as good, but didn't realize some of the unique advantages of a waterjet cutter.
I do love the idea of a Rail gun cutter, though - just not sure how it could really help cut things.