Why would Dragon Quest XI be published by Nintendo? Why would Dragon Quest Builders be published by Nintendo? Despite those games were published by Square? I mean, this isn't anything new to the gaming world. Nintendo would publish the game to take on the cost that Atlus and Sega would have to eat otherwise. And of course this could mean that the Switch version gets things that Royal doesn't get. The same way Dragon Quest XI is getting things the PS4 version isn't getting and legally can't unless it's timed.
But like I said, heh...just wait for the 25th.
Edit: But you do raise a good point, P5 Arena was delayed so this could be the fighting game, so okay we'll wait for the 25th.
All SMT/Persona Q/EO/RPG games on ds/3ds were made and published by Atlus. Bring Square here isn't relevent since Atlus isn't Square.