People who want +2 refresh.
Susan has no player. So her Refresh is inconsequential.
Whether it should be a Power or a Stunt is nothing more than a power level concern. And this is powerful enough that it ought to be a Power.
Look at Father Forthill. He is completely mortal. He has Powers, though, to represent the fact that God helps him out a little bit.
Actually, the True Believer template is generally used on people who are narratively completely mortal. A theoretical template that only allowed this would be the same.
PS: I've been accused of only caring about mechanics, but really I'm just very aware of the separation between narrative and mechanics. That's what this is about.