Because although Sora is the main character of the series The box art is supposed to represent all the KeyBlade wielders in 2.5 which is why it includes the KeyBlades from BBS as well.I'm not sure why, but I think it would be fitting if all the Keyblades shown were ONLY Sora's. Why are Eraqus' and Vanitas' Keyblades even THERE, yet they don't have TAV?