With WordPress, you need a server at all times and the HTML is generated each time you try to access your site. Sure, you can use caching plugins, but it only makes things complex. Eg. You need to now keep those plugins updated at all times, along with WordPress itself. A static site doesn't need a server and can work right off a CDN. It's blazingly fast and it's virtually unhackable. There are no security updates whatsoever you need to keep track of.
Thanks. Not sure why I got downvotes for asking a question though.
Also, I recently built http://blog.winricklabs.com for example which uses my own static site generator. I didn't use wordpress just because it'd be overkill.
