Cats don't leave the toilet seat up. A cat's idea of a good Playboy is one that effectively covers the bottom of the litter box. At least when they sleep all day they don't take up the whole couch. Cats won't crush your legs when they sit on your lap. Most cats are polite enough not to snuggle up to you in the morning with dinosaur breath.
Cats are more likely to be up to date on their shots.
Cats keep your ears warm at night. Unlike a man, a cat can fend for itself. If a cat gets lost, at least it has a tag on it to tell whoever finds it where it lives. A cat is loyal. There's a better chance of finding a cat that is willing to read a book that doesn't have any pictures.