Yeah, my reading was sending me to that conclusion as well. I would need to wind this thing umpteen thousand times with 60 AWG magnet wire in order to be sensitive enough at low amplitude. Wrapping it around a ferrite core was what I was trying to avoid, since I wanted to wrap it around both legs of my home's split-phase 240V mains conductors at the same time.
I was also drawn in by the attractiveness of the air core, I admit it.
I may still give it a try, but I'm considerably less excited about Rogowski coils now. bummer. 