You didn't mention the biggest benefit of server-side javascript -- you get Javascript on client, server, and database. You can pass JSON objects from client to server using Socket.IO and then just save them in MongoDB with ease. You can reuse code between client and server. It's simply fantastic.
Ah, I remember server-side javascript the first time it came around. I seem to remember that it was available as part of Netscape's webserver. I was using it in an electronic publishing project in 1999.
I dare say that the new incarnation is considerably different ... or at least, I hope so.
Judging from the general instability of node.js and company, I say, it's not.