Well yes, Barzagli is phenomenal. But my point is that MSN now have to worry much less about "being in for for a world of hurt", when they go on the attack.
I think that's Chiellini's biggest contribution. He's a hardman, the kind of defender that makes strikers shit their pants out of fear of what happen to their ankles, knees etc.
Barzagli is the better defender overall, but Chiellini is the type of guy who would bodycheck Neymar early on and make him timid for the rest of the match.