Why do you think that? I would guess that the vast majority of NY style operators use a single flour in their dough.
What do you think you can accomplish with a blend that you can't with a single flour?
I've been told by a few owners that they've developed their own special blend. Plus I don't recall anyone having the same crust flavor, look, feel, and texture. I may be wrong and I know everyone has their own technique.
I don't know what you'd accomplish for sure. I can take a guess like different flavor, look, feel, and texture. Just like anything else you'll do your own style of sauce and cheese blend to make it your own special recipe, right?