Quote Originally Posted by FelixZeroAlastor View Post
I assume because they act as his eyes. In a sense he is like Pain that each body can see through each others line of sight. Unless they can Genjutsu all the snakes at once then it's useless.
That's what I was thinking. It shouldn't be difficult for someone of Itachi's level to, especially considering he is a strong genjutsu user with eyes made for this stuff, to put everyone and everything in a genjutsu. Plus Sasuke is there as well who despite seemingly showing greater affinity for ninjutsu would still provide some sort of genjutsu backup.