It's pretty neat for pure Ruby gems because you can stay on the bleeding edge. And I believe that Github would build a gem dynamicly (if you had a gemspec in the root). But for a compiled environment like .NET, I just don't see the usefulness in the short term.
It'd be neat if Nu could pull a project from git, build it, and then put that corresponding binary into the lib directory. But figuring out the correct binaries to add, where they are, etc. would be pretty daunting.
Also, I thought that Github got rid of Gem support? The last I read (and I don't keep up with Github that much) is that they pushed everyone to
rubygems.org because they didn't want to become a gem repository.