I don't know Octopress, this is just my tool and it's probably worst than all the others but it fits my needs

Just for fun is a perfectly good reason for anything!

Also, I have saved a lot of time looking around for existing solutions than just doing it myself. :)

Just saw a little bit Octopress, it seems you need a local server to see your files, I don't like that, Gugodoc produces only static html files. you just need to open them with a browser and that's all

The server part in Octopress (and other static site generators are there just for convenience and to and see how it really works when you host the site I guess.)

Not sure, If you don't run the server you can't see anything because often the templating is done by the server

The Octopress generates static html. No templating at server side. You can host output html to any static host like github pages.