User blog:Assassins Creed Lover/Why can't the two portable system games be on actual systems?

I'd really like to know what ubisoft was thinking when they made two games that would completely help the story... but I don't have a DS or psp cause I happen to own a 360. Tell me what you think... shouldn't they release them for 360 and Ps3? I don't know maybe I'm wrong but...