"I've not heard the phrase "handbag items" before. Does it mean something that is just for show not something that is truly valued? (That's my best guess, but I'm dubious about using it without your confirmation!) "

Your definition of 'handbag item' is right, AmberLee. A dog that is acquired as a fashionable accessory can be discarded like a handbag.
Breeds which become popular at a certain time are at risk for this happening to them.
Marie