There has been much research for many years that prove these collar methods are inhumane and usually ineffective. They cause physical and emotional damage. Why would anyone want to use these on dogs? They are cruel.

Prong collars can cause Intervertebral disc protrusion
Partial or complete fore- or hind-limb paralysis from spinal cord injuries
Damage to the vagus nerve, affecting the functioning of major organs, including the heart, lungs, liver, bladder, spleen, and kidneys
A crushed trachea, with partial or complete asphyxiation
Crushed or fractured bones in the larynx
A bruised esophagus
Sharp increases in pressure inside the head, which can cause brain or eye damage and sometimes prolapse of the eye
Bruising and damage to the skin and tissues in the neck, resulting in the formation of scar tissue
Fainting

Shock collars can cause dogs physical pain, injury (ranging from burns to cardiac fibrillation), and psychological stress, including severe anxiety and displaced aggression.  The anxiety and confusion caused by repeated shocks can lead to changes in a dog’s heart and respiration rate or gastrointestinal disorders. Electronic collars can also malfunction, either administering no shocks at all or nonstop shocks.

Choke collars can result in a crushed or bruised trachea, with their larynx or a fracture or dislocation of the neck bones, among other injuries. A choke collar that is too big around the dog’s neck makes it is easier for them to chew the chain, which can also cause damage to their teeth. A quick jerk delivers an immediate punishment. They have been scientifically proven to cause injured ocular blood vessels, tracheal and oesophageal damage, severely sprained necks, cases of fainting, asphyxiation, transient foreleg paralysis, laryngeal nerve paralysis and hind leg ataxia.

It has also been proven positive reinforcement training uses a reward (treats, praise, toys, anything the dog finds rewarding) for desired behaviors. Because the reward makes them more likely to repeat the behavior, positive reinforcement is one of your most powerful tools for shaping or changing your dog's behavior and is much more humane. It's now 2021, it's time we put an end to inhumane devices that cause innocent dogs great harm.