Board Thread:Naruto Discussions/@comment-26993711-20160107221250/@comment-9782468-20160109073454

@LSSJ4, you can't argue that something would be ineffective just because they didn't use it. That's not an argument, that's aggressive speculation >_>

The Rinnegan can't use Amaterasu. So it's safe to say that while the Rinnegan is the superior dojutsu, the Sharingan has abilities that the Rinnegan doesn't. So just because the Rinnegan is more powerful, it doesn't make it automatically immune to Sharingan techniques, including Genjutsu.