If the purpose of Elo's system was to predict the outcome of a game between two players who have no or limited prior interaction, it can be "misapplied" to grea

If the purpose of Elo's system was to predict the outcome of a game between two players who have no or limited prior interaction, it can be "misapplied" to great effect. While unfairness and randomness (starting as black vs. white in Chess) can bias and increase the variance of that estimate, it is still better than tossing a coin.