You can leave a dog alone in your house without worrying so much about what it'll break. A dog gets a new coat every winter. Dogs are not so careless about leaving puddles on the bathroom floor. A dog is less likely to leave a filthy, stinking mess for you to clear up. For a dog, a wet nose is a sign of GOOD health.
Men are even less useful for testing cosmetics on.
Dogs don't wolf-whistle. Your dog will never refer to you as 'a bitch'. In disaster films, the dog is always far more likely to have a miraculous escape. Dogs do not waste money betting on the dogs. You can stop dogs getting too randy by throwing a bucket or water over them.