Many money laundering techniques use a commodity in the process, that doesn't make it not money laundering.

Just because using a tumbler itself is not against the law, if you use it to hide the source of income, it is still money laundering.

You can't get around financial laws by using property instead of currency. "A payment made using virtual currency is subject to information reporting to the same extent as any other payment made in property."

https://www.irs.gov/uac/newsroom/irs-virtual-currency-guidan...