We started leveraging the rhino JavaScript interpreter back in 2008 when we were on a project with Union Pacific. Of course, at that time, there were other ways of writing scripts ( perl and python come to mind ). We, however, found the power of JavaScript and the fact that we could tap in to the Java libraries, while also bringing an easy single file install on Windows, Mac, and Linux, to be a major selling point.
Every script we produce uses this method.