No, it would not be worth your time learning git to write a blog. However, version control is pretty fancy and can come in handy in many different things - not only in developing software.
Your new workflow would not change that much from your current, except that you would not be editing in a WP web interface but in your favorite text editor - or e.g. Mou for having markdown syntax rendering enabled. After you created a page you would add it to version control and push the changes to the GitHub server (if using a gh-pages branch the page would also be rendered automatically) and you can either create/edit another topic or keep editing that page.
The best advantage I see in Git is decentralized version control i.e. you don’t even need a working internet connection to use git - you can have a local git repository with all its benefits and a smaller footprint than SVN.
But as I said: Just for writing theses posts it wouldn’t be worth your time.