Maybe, but agree that if a thief find this "weird" cards by taking your wallet, the chance that he find what it means.. and to actually find a way to brute forc

Maybe, but agree that if a thief find this "weird" cards by taking your wallet, the chance that he find what it means.. and to actually find a way to brute force is really low. Compare that to a plain paper with a password written on it! But yes.. security is all about trade of.