Well lets be fair it does show you are at least Rescue Diver Trained, have completed a minimum of 50 dives and have committed to additional training. So it does hold some value over and above AOW or Rescue.
I agree it shows the diving shop/operation you are a fool who will easily be parted with your money. It's of immense value to them.
I can't think of 5 specialities worth doing... Nitrox, Deep (for holidays), Wreck (for holidays)... That's about it.