So you’re a PADI DM/AI? Have you read the Specialty Instructor Manual that PADI puts out? You don’t know of any agency that stands behind this method because you don’t actually pay attention. When RECREATIONAL diving PADI says (and I agree with) that you should use your Dry Suit for your buoyancy at depth and use your BCD only in an emergency or while at the surface. I realize that you are a Mass diver and you probably believe in wearing 40 pounds of lead with your dry suit because no one ever taught you any better (not different - I’ll just say your training was flat out wrong in this instance). In recreational diving you should need butt loads of weight. In recreational gear with a dry suit I wear 8 pounds. No, I don’t expect you to have the buoyancy control I do. You’ve already shown you have little clue as to what is actually going on because you don’t even read the manuals to develop an informed opinion.
Technical diving is a different story. When equipped and trained as a Tec Diver you use the Dry Suit only to eliminate squeeze and you should use your BCD bladder for buoyancy if necessary. Again, I don’t use a whole lot of air for buoyancy and I wear NO weight when Tec Diving. I’d hazard a guess that you use doubles and aren’t adequately or even actually trained in their use.
The reason for the difference? Many. Primary reason given? Recreational Divers aren’t trained to handle that many items of buoyancy control. When you task load a Recreational Diver with remembering where they have air to vent you run a higher risk of injury.
Just a little bit of education for the unwashed masses.