Maybe because it takes a lot of effort to implement all that stuff and it's still a big deal for a lot of people. This is also a regular blogger why not? Also there are probably a lot more out there, you see this one because people find it upvoteworthy.

You could ask the question for almost every blog post, i think this one is not much different why posts on codehorror are written. There are a lot of good reasons to blog, just Google for it.