Board Thread:Versus Debates/@comment-30426414-20161228222316/@comment-25122992-20161229130559

Yeah, he had the cursed mark, and it's surely powerful, but it has it's own drawback as well which was already explained in part 1 (it feeds on the user's own chakra and corrupts his body), so it's not really that better compared to Susanoo. Oro's substitution isn't without drawbacks as well, taking a great tool on the user's chakra reserves, it was costly even for Oro himself.

C`mon, it was clearly stated that Itachi didn't want to win the fight. The whole objective of Itachi was to draw out Oro from Sasuke's body and seal him, otherwise Itachi just would've let himself be killed with Kirin. But it doesn't really matter. There was no guarantee Sasuke could force Oro back in his body again, and in any event he couldn't know that Itachi wields an ancient relic able to free him by sealing Oro. So for Sasuke, letting Oro emerge from his body equals his own death.