Is this coming out of MS Research as one of these "look, we came up with a way to do this" but it's not something that has a concrete use case? It reminds me of their MSR's project where they made a bootable operating system kernel in C# which, if I recall correctly, influenced the Midori project, elements of which have percolated into refactorings that have shipped with Windows 10. It also makes me think of F# which is a very useful language on its own but serves as more of a test-bed for future features for C#.

I suppose if the learnings of Bosque find their way into TypeScript that might be useful but I don't see a practical use for Bosque as it is. Either that or I've completely missed the point.