It doesn’t have to be by default, but I certainly believe it is something used very often. I picked up the patch today and played for a short while:
A simple soccer ball; the faces are getting extruded in patches based on the original geo’s face index (a truncated icosohedron). I’m just comparing the iteration number and the iFace attribute I set.
I’ve seen it in other software where you press a button and it will generate the iteration count and the iteration sum as attributes, so they aren’t there by default, but can be with ease. In my opinion thing it’s a UI thing, we can do this manually each time we need them, but functionality wise I feel they basically go hand in hand.