The cat's basic nature differs considerably from that of the dog. They are nocturnal hunters. They climb trees. They are very flexible — if their whiskers can get through an opening, so can the rest of the cat. A dog accepts restraint pretty well, but cats hate it. Many cats simply refuse to wear a collar, struggling constantly while it is on. [So do some dogs, but not many.]
Because of a cat's propensity for investigating small places and climbing trees, collars may become hung up on something. With a regular buckle like this, the cat will have great difficult getting disentangled.
The same is true for this type of "snap" ("seatbelt") buckle. They look like plastic junk, but the company guarantees them not to break (with free replacement if they do). They don't pop open on their own if properly closed.
You might have wondered why the cat looks a little angry in the first picture. This is why. She was missing for four days, returning home thin and a little dehydrated, and with her collar in her armpit. Apparently it was a little tight, having been adjusted for her neck, not her neck and shoulder.
Here's a close-up of the wound. It's too infected to close up today, but we've cleaned her up, and she is taking antibiotics and pain medication. Cats are such great healers, it will probably be half closed by the time the infection is under control.
Here's the buckle on a "break-away" collar. If the cat pulls hard enough, the buckle just pops open. People complain about the cat losing its collar and having to buy more collars, but the collars are pretty inexpensive — certainly cheaper than treating such a wound. "He keeps coming home without his collar". The key words in that phrase are "He keeps coming home". Some cats that get hung up just don't come home. Somewhere in a bush there is a little kitty skeleton hanging by that collar we didn't want to lose. Wish I had a picture of that.