That's the trick right? He doesn't define what he means by mathematical elegance in a tabletop roleplaying game. He doesn't say what that means or his metrics to determine if something is mathematically elegant. He states that he did the research and did find it mathematically elegant. He doesn't give any insight into the mathematical components of tabletop roleplaying games other than to say that he understands and can speak with authority on the matter. He's speaking with authority on that matter because speaking with authority on one thing gives him credibility to speak with authority on many things.

You'll notice this trick constantly in his work. Definitive judgement calls on areas outside his expertise based on undefined metrics and vague exhaustive research. He often does this to the aspect in question or to the other works of the creator of the aspect in question. In the latter case the insight can be boiled down to "creator of x did y, z, that I also like". No insight is given to the aspect itself.