Quote from 717FX
Place cats around your house and your house is protected forever from creepers. That's why creepers exist : to have a danger for your constructions. That will be too easy ! Creepers will lose all their interests. Even now, creepers aren't much trouble. I think that even at hard, the game is too easy.
EDIT : Ok, I admit I posted that too fast : I didn't know that cats can be killed by other monsters, but I also learned that we can breed them. So, when they die, you can easily put other cats instead and it's the same problem.
since the whole and only point to having a cat is to deter creepers, don't have cats if you want creepers to attack you.