Well, ELO has been proved useful in various domains (it's used to evaluate product quality in the agroalimentary industry for instance), and compared to various

Well, ELO has been proved useful in various domains (it's used to evaluate product quality in the agroalimentary industry for instance), and compared to various rating systems in different sports. So you can't actually say that "it has never really been demonstrated that Elo ratings are more accurate than other approaches would be."