One thing I've learned being in various athletic venues over time is that things change, and change often. I didn't say the SEZ club was going to fail (I actually really like the premium seating option it creates at JTS) but that isn't saying that 30 years from now, Jack Trice will look exactly the same either, or that the current club amenities won't need a major overhaul. All I was getting at was that the material could have been chosen to ensure the stadium is flexible if trends in stadiums, fan support, etc., change over time. Jamie knows this too, and I wouldn't be surprised if he made a decision about materials based upon future venue options & scenarios that may occur down the road.
They claimed one of the reasons was for sound. I am sure flexibility might have been a factor also. Also a possibility that it could include the lower corners adjacent to the present End Zone Club for expansion of the Club if it proves popular.