Sure, Bitcoin Mixing prevents to track your payments severing the links between your old address and the new address by sending Bitcoin from you to other people and Bitcoin from them to you. It also randomizes the amount of the transaction and adds some delays to the same transactions.
But it requires a provider that offers the Mixing Bitcoin service.
Probably this provider may keep track of your transactions and communicate them to the authorities in case of criminal activity.
Tumbling is a form of “washing” of Bitcoin that attempts to break the public connections between you and your Bitcoins.
Your Bitcoins will move from your wallet to LocalBitcoins (or any other wallet or exchanger) and then go to the thumbler's portfolio and then to the marketplace's portfolio.
But the Tumbling service and the market will retain a percentage of the coins transferred as fees. To be precise, the Tumbler takes a commission on the amount transferred, while the market takes a small percentage of the purchase price.
Probably about 10%, then: are the criminals willing to lose a percentage of their earnings?
Bitcoin ( and it's blockchain implementation ) has an inherent " taint" problem , and falls far short of the original concept as proposed by David Chaum.
BTC transactions would be better described as quasi-anonymous ( if this were not true there would be no need for mixing services ) .
The taint concept comes from paper money , where every person who handled it will leave minute traces that indicate where it has been ,
even DNA !
That taint cannot be washed away , and tumbling and mixing services only serve to obfuscate , they do not entirely remove it .
But it doesn't have to be this way , there are already much better implementations of the ecash concept.
The original work of David Chaum is superb , and I can provide some good links if anyone wants to read more .
BTW , is it just me , or is there a definite smell of script kiddie around this whole episode ?
The amount of money in those wallets is TINY considering the scale of the damage done ...
... pocket change to most Ransomware Scummers ( I prefer that word to " Scammer " )