Obviously it is the method for establishing an initial rating that is the most absurd in backgammon. It probably is fine for games of pure skill, but makes no sense at all in backgammon where the worst player can beat the best player by pure luck. Even in a game of skill, it could be distortive if a highly rated player happened to lose for some reason other than being outplayed, e.g. by timing out. But in backgammon, distortion is almost guaranteed in a signficant percentage of cases.