It could be because the author took time to give a detailed explanation of how he implemented it. It shows to a beginner programmer that (s)he could automate simple tasks like this easily and a way to approach it.
I teach for a living (music technology), and it's incredible how badly a lot of things are explained (in all fields). Clear explanation and worked examples, combined with appropriate progression in difficulty is what makes for good learning, and I think this is a good example.
I spend a lot of time here, mostly in awe of the expertise of others and hoping to learn something from them.