So this is very reminiscent of the big certifications map that CompTIA puts out from time to time. It lists the major certs by difficulty category, but it also ties them to a role pathway, answering that questions, "if I want to be a data scientist, what certs would be advantageous to me?". It looks like this site uses that approach as a means to efficiently focusing learning efforts along a defined pathway, rather than the "spray and pray" approach.
I can see this site as something of value to folks that need that kind of guidance. In a world where mentor/protege style relationships (which to me are the BEST way to accomplish this), sites like this can help clear up the confusion.
/r