I understand how competition can be seen as variable reward dressed up. On the other hand, in an attempt to classify games, separating the two components competition and chance is still useful. I think that chance is to be understood as a component completely independent of the player's skills. This allows to distinguish competitive games such as chess (competion with skills) and yahtzee (competition with chance) for example.
Even competitions of chance have skill components (unless they are completely random) and competitions of skill have chance components (who do you get matched against). Even in chess, two players playing against eachother will not always have the same outcome, it's not completely deterministic.
