The difference is that ci-type of solutions might end up requiring maintenance for a million and one reasons. This won't and building it took me roughly the same amount of time it would take me to navigate through a ci-solution and test that I've set it up correctly(3 hours in total).
I find it fascinating that you'd go to all the trouble to build what essentially breaks down to a custom static site generator but you then balk at using an off the shelf one with a build script.