I believe node is a fast I/O non-blocking platform, which sounds like it does not have to be only network applications.
So I wonder if there are any cases of which using node, not as a server, would be of benefit? E.g. for writing command-line programs.
Grunt is a great example. It's a JS task runner that most people use as a build tool. Unless you make it run a server for you, you will communicate with it solely via CLI.