You can't have it both ways though? . Legally they're not property as they do not have to be controlled, on leads or confined, can go roam (and shit in peoples gardens without ramifications to the owner - and I say that as a cat owner myself) fight, breed and hunt and you do not legally have to report one being hit by your vehicle like you do a dog. And despite what people think, hitting a dog with a car has to be reported so the driver can seek damages from the dog owner. It's not even for the good of the dog and owner.
Cats also fuck off and move in with other people. Or they just disappear for years.
Chipping dogs is law (though never have I ever seen anyone actually get prosecuted other than professional breeders so as usual, it's only the easy targets) but chipping cats is for convenience if you cat is found by a rescue or you own a microchip cat flap.
My cat is chipped purely so I have a bawhair's chance of finding her if she goes missing.