Well on a dog that doesn't respond to the choke collar and keeps pulling on it, the chain never has the chance to release, thus choking her till she threw up. With the pinch collar she doesn't pull. I have to reminder her to heel every now and again when she get excited, but she's extremely well behaved once the pinch collar is on.
I would never leave a choke or a pinch collar on a dog. She has a normal nylon collar that she wears when I'm not walking her. She was on leash in those pictures, they just edited the leash out.