Is the use of server side javascript prevalent? Why would one use it as opposed the any other server side scripting? Is there a specific use case(s) that makes it better tha
We use javascript on the client because it is there, not because from a list of languages it was our choice. I wouldn't choose it for any chore on the server.
You can run any language you like on the server, in fact, as many as you like.
javascript is reliable and easy to use, but it is just too labor intensive for common tasks on the server.