Yep, I wanted to avoid building in a web server into the static site generator, since it complicates that product.

The cache server definitely adds complexity and more so than a static site. However the complexity is setup and done once on initial server setup. On-going, the multi-process of a site generator adds up. Granted its one small step which as you say most already have scripted tasks.

Answering the first comment, the use case was something to play with for my personal site which I wanted to share if others found useful.