People forget he uses one length clubs. Hitting a 6 iron out of the rough with a pitching wedge head or 9 iron is quite the advantage. Longer club means more force. Simple physics really.
I switched to single length irons a little over a year ago. Best decision I ever made. Steel shaft Wishon. When I was being fitted the guy that made them for me said something that struck a chord...more or less, "when you play golf you should enjoy it, not worry about what you are doing wrong."
The simple fact is besides the drive I have one swing to repeat now...no longer have to worry about length of my irons and adjusting stance.
I only play maybe once or twice a month- got my first hole in one of Memorial Day. No complaining out of me on single length irons...makes total sense. Honestly, I am surprised more people aren't doing this, it is a no brainer.