Here are a few reasons:

  * A small, yet useful set of core APIs (http://gwan.ch/api)
  * Applications are recompiled on the fly when a change is made
  * A "no compromises" attitude to performance and software design
  * It supports legacy applications written in CGI-style without the cost of CGI

See this article for an interview with the author of the project[1]

[1]http://salem-news.com/print/19923