Supporting this Markdown syntax and the interactivity on top of it would make the task tracking a lot easier. A potential use of the feature on this website would be in pages where features of the upcoming releases are listed and updated with green check mark as they are implemented. Also, it could potentially be used in wiki posts to allow others to work on a bunch of community taks and mark the progress quickly.
https://github.com/blog/1375-task-lists-in-gfm-issues-pulls-comments