> "most idiotic devices anyone could own"

Ever been to Chesterton's Fence?

Hypothetically, some people who own such an idiotic device might have pets that bring in lots of dirt from the fields, lose lots of hair, and get a little bit agitated by the normal vacuum cleaner but more or less ignore the robot vacuum.

Cats aren't that bothered by vacuum cleaners unless you come at them with it and they normally just run into another room. Never seen a dog that bothered by them.