What makes static site generators like Jekyll and Hyde better than XML and XSLT?

The idea seems to be very similar by keeping actual content separate from the final output rendering开发者_StackOverflow so that changing the template or styling is trivial.

2 things that spring to mind:

1. You don't have to write the transform engine yourself
2. You don't have to write your pages in XML; in Hyde, for instance, you can write your pages in Markdown and use filters to convert it to HTML

UPDATE: Regarding the idea behind it, I think the main goal is to get (most of) the benefits of a dynamic blog or cms engine, but all the performance (especially w.r.t. memory footprint) wins of static files. As a secondary benefit, this enables you to write your content in your favorite text editor and version it using your favorite version control tool.