Actually, for money laundering or for black market actions, everything can be traced, because in the end they will convert it to fiat, and many exchanges are currently required to do KYC. indeed from the start it was debated that bitcoin has a negative side, so the government is still considering it, until now even the regulations are not clear, and in this case for bitcoiners it is of course difficult to take legal action if there is a criminal action against their assets. but this is something that naturally happens, because wherever there are pros and cons there will always be actions
With the decentralized nature of bitcoin, I don't think bitcoin can be traced. The movement from the open source wallet to the exchange platform before converting it to fiat will be cumbersome. And some launders would used per to per straight from the open source wallet and you don't know who own the wallet because there is no name attached to the wallet and that make it anonymity decentralized out of authority control. And regulation affact only exchanges. Money launders use p2p than using exchange.
Well, tracing is not really impossible even if a person is using a decentralized P2P service for converting the Bitcoins to their local currency, the authorities can trace the Bitcoins that are sent from the launderer to the P2P merchant and they can get to the merchant to inquire who they sent the money to for that specific transaction and when they check the bank account or any account used to receive the money, that will trace back to the launderer.
However, none of that actually makes Bitcoin a bad thing, even if criminals use it or money launderers launder money using it, it's just a currency and it is not to be blamed for those crimes. As everyone already said, crimes were there even when Bitcoin was not created, so that should make every currency a criminal currency.