On of the main reasons I like static site generators so much is that it makes maintaining a website more like developing software. I have 'sources', which I keep in a Git repo for powerful versioning, I 'build' the website from the sources, and then I 'publish' the final product... which is the user facing HTML website.

Developers just find that workflow sublime, and since we're often making websites for ourselves or for our companies, it only makes sense that we've started to use tools that fit our mentality.