To be honest, Mattel may expect to sell many, many Batman figures, and I don't mean individual figures, but variants and different versions. How many of these K-pop characters they expect to sell? Perphaps they think most people will buy one of each and it's done. So they make a good version of these with all the accessories they think the could add.
With Batman, they may spread out these accessories in order to sell many variants. They're already doing variants in the kids line. So don't get your hopes up that the first collector's Batman will come with everything we want.