I've been building Node.JS based software for over 5 years, typically developing backend services to support mobile applications in the form of an API. Additionally Node is great for creating CLIs (Command Line Interface), which I create and utilize regularly to support automation efforts. Some uses cases include (but not limited to), setting up or modifying project files (eliminating steps to get started on projects), data shaping (taking some data source and converting it to meet the needs of a new/different system) and lots of little helper scripts.