Board Thread:News and Announcements/@comment-34277398-20180120160317/@comment-734582-20180128135657

Lorenzo.r.2nd wrote: But he didn't defeat kurama,so it doesn't matter what we think couldve happened. We can't prove it, so it's useless in this discussion. ... what does sealing him in someone consist of then? Did Itachi not defeat orochimaru by sealing him? Did Sasuke not defeat Orochimaru by sealing him? Did naruto and sasuke not defeat Kaguya by sealing her?

He only needed Kushina to bind Kurama, so that he could split Kurama and so still make use of him. If the intent was to simply defeat Kurama (which would've been dumb), he could've sealed Kurama in anyone.