When your cat retracts her claws, the sharp points are protected from becoming
dull or damaged as she walks or runs around your home. Cats that live outdoors
or are allowed to go outside must always keep their claws sharp—and claws don’t
sharpen unless you can poke someone’s eye out with them (or at least scratch open a
bag of kibble). That ability to inflict damage also comes in handy for defense of
course, even in a housecat who hasn’t seen the outdoors since she got fixed last
January.