Perhaps I just don't understand what "money laundering" means, but I don't really see how bit-coin is of any use whatsoever for money laundering.
Money-laundering, as I understand it, means to disguise the true origin of ill-gotten funds, so as to make the income appear legitimate.
I think there's confusion in the two different means of the word "disguise". In one sense, it means simply to hide or obscure. In another sense, it means to make something or someone appear to be something else.
Bank robbers wear a disguise in the first sense. A bank-robber doesn't wear a Richard Nixon mask because he wants people to think Richard Nixon robbed the bank. He just doesn't want to be identified in a line-up. This is the same kind of disguise that bit-coin offers. And even in that, it doesn't really stand up.
But I think people interested in money-laundering are using the other sense of the word: they want to be able to actually spend their ill-gotten gains without arousing suspicion. They need to make it look like legitimate income. That is why Walter White bought a car-wash.
Merely obscuring the true origin of your money is useless. If the government is even a tiny bit curious about the true origin of your money, you're already well and truly fucked, whether or not they can ever figure it out.