This means nothing, its going to be put into GO as a special costume for Mewtwo like the Pikachu hats and the Squirtle sunglasses its only going to be in the movie the same amount of time as the original. You see the two Mews fighting in the trailer near the climax of the film and he isnt wearing it, if its going to be a main focus of the movie hed wear it more the only big difference I expect them to make is Mewtwo using his megas. Otherwise its just a remake.