Implementing a ranking system in the game may help in a better gameplay overall. It will help the newbies out and they will not get matched with the players of higher rank than them or lower.
This will give the newbies a chance to improve and learn the mechanics of the game before getting in the actual battle.
By this way the players that have already attained a higher rank will be matched with the players of that rank thus improving the overall playability of the game.