Well, like any other Pokemon game, I would say yes. Since after the game is finished and all America would probably want to add a extra challenge for those who beat the game. Maybe add a secret Boss Trainer battle. I dunno, it's up to Ame to decide if she wants to add it or not. But meh, there's an extremely high probability of a battle frontier coming out when the game is finished, but for now. You might as well do some senseless grinding on some Pokemon.