I looks like they're only for small dogs...and if a small dog needs a muzzle (nippers and ankle-biters), at least these are a LOT less nasty-looking than a cage muzzle. The look of a cage muzzle is so off-putting to owners that maybe those with nippers would be more willing to use these instead.

Seriously doubt people would use these just to be funny...there are plenty of real costumes (that are more comfortable, more humiliating) that are available. Muzzles are for real situations however they look.