If a grid is used, then that means it is worthwhile. It is worth the effort of setting up and using it, regardless of what it is used for
Kate Booth uses Sim-on-a-Stick in a network manner so that a class of many students log into one instance is SoaS. By definition and use, that's a grid IMO.
When I build something like Hax Unit on a stick, unconnected to the web, is that a grid?
When I converted the 16 region Enclave Harbour into a single mega region on SoaS, was that a single user grid?
I think the definition of 'grid' is perhaps yet to be fully defined - just like photography wasn't defined as an art medium when it was invented.
Nice thought provoking post =)