I mean considering the anonymous nature of cryptocurrencies around the world, I think that it would be a good idea to use it to hide your money by converting cash into cryptocurrency which can only be accessed by yourself and anyone who has knowledge of the secret passcode of your ledger.
Is it possible to do so or the authorities have countermeasures in place in order to catch people red-handed when laundering money through cryptocurrencies.
I believe there has been cases where the police where able to track transactions from a wallet, into a bunch other addressess, and then went to the exchanges with this, and responsible people got punished. Still requires some slip-ups on their part though.