To be honest my biggest reason for getting my AOW cert was to get better service from dive operators in tropical waters. It’s not always the case but I have experienced showing up in Hawaii and the boat crew looked at my OW card and said "ok, we are going to a nice easy reef in shallow water for the day." Even though I had more than 50 dives at the time in cold California waters..... they don’t look at your log book. The following year I used the same operator in Maui, and when I presented my AOW card the story became "hey, are you interested in diving the backside of Molokini and seeing some sharks on a deep drift dive?" I guess the cert gives everyone more confidence in your implied abilities ;-)