Ping I-20 Irons w/ TFC 169I Graphite shaft

I was at GG the other day and just for kicks I hit an I20 7 iron with the TFC 169I stiff shaft. I hit my 7 iron with CFS reg. flex shaft around 150 - 155 yds. With the TFC shaft it was 165 - 170 yds. Is the difference in yardage the stiff shaft verses regular shaft? Or the graphite shaft verses steel shaft? They both went straight. Why does it seem like graphite shafts are frowned upon?

Im no expert by any stretch but do play graphite shafts in some of my clubs. My guess for the added distance is more club head speed/ball speed due to the lighter weighted graphite shafts. I notice a few yard more distance with my graphite sticks vs my CFS shafts in my i20s but have a tighter dispersion with the steel CFS.

TapAhoy!