For practicality's sake, let's just say this Millenniumon is feral and doesn't have the mental fortitude to use his dimension-affecting attacks yet. 

Besides, if we followed all the fluff in profiles, things would be even more ridiculous than they already are. Do you really want a Seraphimon capable of replicating the Big Bang and an Imperialdramon or Ebemon that could casually blow up a planet?