If you read to the bottom of the site, you'll find that the author agrees with you that the end result was not particularly useful:
> Overall, having spent a significant amount of time building this project, scaling it up to the size it’s at now, as well as analysing the data, the main conclusion is that it is not worth building your own solution, and investing this much time. When I first started building this project 3 years ago, I expected to learn way more surprising and interesting facts. There were some, and it’s super interesting to look through those graphs, however retrospectively, it did not justify the hundreds of hours I invested in this project.
But calling it a vanity project seems overly dismissive. Sometimes you start a project and don't know how it's going to end up. Sometimes it's the journey and not the destination that makes a project worthwhile. I think Felix deserves a lot of credit for writing up his conclusions and sharing them.