Board Thread:Naruto Discussions/@comment-3568954-20140806112253/@comment-1512913-20140808195014

The difference is that chakra transmigration actually effects the physiology of said individual, meaning the transmigrants' bodies produce said chakras rather than simply having a limited amount. So if you insist that Kakashi will have the Sharingan long-term, then he must be Obito's transmigrant, otherwise it's temporary.