The subject is not me, by typing a few words can you really access a private wallet with this site? for example, I typed you it gave me a private key with an account which has a zero balance, but if for example someone were to type a correct word can they really open the wallet in question?
You can use any word or character as your passphrase when creating a brainwallet. For example, you can use the words "hello", "bitcoin", "yes" and so on to generate a private key.
There have been people who have used simple and guessable words as their passphrase and due to obvious reason, those wallets are not secure.