So I'm trying to understand the benefits behind this as opposed to using a normal blog hosted with Github Pages? Then the posts would be visible in the repo.
It's pretty simple in its current form, but if one were to add user authentication then it would be possible to do anything implemented in the Github API.
For example, this project is using issues in the purpose of posting/commenting, but theoretically you could use them as a general purpose database.
If it is for having comments within a Github Pages blog, I found a solution that I wrote about myself about using a normal Jekyll hosted on GH Pages that pulls comments from Issues: http://seanlane.net/2016/Hosting_comments_within_issues_on_G...