Mental stimulation is a huge thing, especially for working breeds. I have to keep Tornado-dog's brain busy or he starts using it by himself - to mostly unappreciated results.
I was always taught that a prong collar was to be used just long enough to get the dog to respond to leash corrections. Once the dog understood what the "quick jerk" of the leash meant, the prong collar was eliminated and the leash correction itself was sufficient.
That's one reason why I think that trainers tend to overuse and overrecommend them. If your dog is an obedience title bearing dog, then why continue to use a prong collar? The dog is fully trained. The dog doesn't pull or run or not recall, etc. Corrections are rarely needed and the dog responds quickly to a verbal correction. So why continue to put an aversive training tool on the dog. Same with shock collars.
When we took Tornado-dog and Cat-dog to a beginning obedience class, there was a young (8-14 months) border mix in the class. She was very hyper and excited. The trainer had the owner use a prong collar. Even without any movement of the leash, the dog yelped and cringed every time the prongs made contact with her neck. The trainer's answer was to recommend using plasic prongs. The truth is that dog had no need for a prong collar. She was very responsive to treats, eager to please, and quick to learn. She just needed to burn off some energy before going to class where there were so many distractions.
I use martingale collars. The main reason is because I don't need to switch out the collar for walks, etc. With harnesses and haltis, it always became a production even if it was just to go outside to potty. And when you're in a small camper with two large dogs, the quicker you can get them out the door, the better.
I mentioned on the other thread that behaviorists are focused on resolving the underlying issue behind a behavior. If a dog is leash reactive, they are going to identify WHY the dog is leash reactive and work to change the dog's emotional response. A trainer is focused on getting the dog to perform a specific behavior regardless of the underlying cause.
The reason most behaviorists do not use or promote the use of aversive tools and methods is because those don't resolve the underlying issue. Behaviorists are also a fairly new field and as such the people in that field have been trained in newer methods and understandings of dogs.
Trainers are more likely to use aversive methods and tools, because they work quick. Owners want to see see fast results. Also, most owners look for trainers with a reputation. To have a reputation, they have to have training for some time. So, a trainer is more likely to use old methods because that is what was done when they learned - many come from the "alpha dog school of thought". And few trainers "go back to school" to learn new methods. They tend to the adage "if it ain't broken, don't fix it" and since their goal is to get a certain behavior, they aren't necessarily concerned with how the dog "feels" about the method/tool used as long as the dog does the behavior.
Dogs do have a heirarchy. However it is not a simple "you alpha me beta" system. Studies have found that the heirarchy differs between feral, street, and pet dogs, as well as between individual groups within those types. And some groups/packs don't even have a heirarchy. But the main thing is that dogs do not see humans as their "pack". We are not dogs and dogs know that. We are something different that they are attracted to. So, using alpha-based training methods (like biting the dog's ear, alpha rolls, never letting the dog on your bed, and so on) are ineffective and will do more harm than good. It's like you going to the DMV and being told "drop your pants and cough" - you know what that means, but it makes no sense for the DMV to use it.