Ive been on pokemong GO charmander event for few minuties, in a park in Brasilia. And man, that was crowded. Thousand of people with their phones playing pokemon GO, and a very diverse demographic. Youngs, adults, olds, entire families, boys and girls of every age.
Is really difficult to say that every one there is a nintendo player.
If Nintendo want somehow to attract non nintendo players to switch, the easiest choice seem to be aiming for the pokemon GO players.
So, integration with pokemon GO is a right thing.