I think that for most game players, outside of the top-N group who just want to be at the head of the list, rankings are largely a mechanism to facilitate playing good games, where good is generally defined as close games where both players feel like they could have won.

There's an interesting question about how you rate players who use fundamentally different strategies. For instance in RTS games, should you match boom vs blitz players of otherwise equivalent elo? Or should you instead (try to) construct a classifier to determine which type of player someone is, and then have a rank against each other type of player and match them according to that rank?