From the front page: "JSDB is JavaScript for databases, a scripting language for data-driven, network-centric programming on Windows, Mac, Linux, and SunOS. JSDB works with databases, XML, the web, and email. It is free and open-source. Use it as a JavaScript shell, to run CGI programs, or as a web server."
But, that's kind of a silly reason right? It's obviously a general purpose server platform. Nobody would say "NodeJS/perl/ruby/python/PHP/C++/Go/Java is for databases".