Yeah, I am sure the producer of the game is thinking up bullshit reasons for a matter he brings up himself in an interview...
It's a more PR-friendly answer than "we needed to make 8D stand out from 8 a bit more"
there is no real hardware reason other than if MK8 stores unique copies of everything concerning the items with the items and no, they don't
MK8 is a lean game from an execution perspective
I mean DD came out on the GameCube and that had some intense items
but still not intense from the execution perspective