I think I just preferred multiplayer over collaborative as a term, risking the misunderstanding. It's a design tool, it doesn't have a game-loop, but it is built on a game engine, and was intended to be more physical and provide more tangible feedback similar to games.
The use cases for Grid are pretty broad, we've seen people use it for a visual personal journal to storyboarding games and movies to architects planning projects with their clients.
It's light weight organization for visual thinkers that you can invite anyone too, and we've seen it used most heavily amongst those in the creative industry.