Many people use crypto to launder money, this is true. But why does no one pay attention to money laundering through other currencies?
The reason is simple because this forum is about cryptocurrency so the concern of discussion is money laundering using cryptocurrency, secondly because cryptocurrency has become a trend lately so that it received more attention and the last, money laundering with other currencies has often been detected by law enforcement agencies, but it is not explained in technical detail for the purpose of investigation, so the references of discussion are limited.
You have much to learn about the real world haha. Banks are the biggest crooks and big organizations too, they claim to be transparent and do their audits every year with big companies but still hide a lot of dirty money in the books.
Dollars are used for laundering not really because of supply but because it's fungible and it fits into the banking system so well.
Your statement is not the opposite of what I said, most of money laundering cases are occurring within traditional channels. This situation is not going to change in foreseeable future. However, I disagree with your claim that cash is more fungible than bitcoin. Both physical cash and bitcoin are fungible, otherwise they wouldn't be considered money whatsoever. Fungibility of bitcoin is more natural than that of cash, because it is guaranteed by immutable code. It is rarely used in money laundering not because of non-fungibility, but because of higher traceability and immutability. Money launderers and criminals don't want their illicit transactions to be written on blockchain. Instead, they strive to leave as little evidence as possible. Banks allow for that, bitcoin doesn't.
Every criminal act, which get additional/margin/benefit is automatically acquired is money laundering. In money laundering, the perpetrator usually places the proceeds of crime into the financial system or changes its form, including being stored in a bank, being smuggled into other countries until it is converted into other assets such as gold or property. Then the proceeds from the crime were transferred, distributed and disguised with the aim of hiding their origins so that they would be difficult to trace. The latter is a combination of proceeds of crime that already appear legitimate to be enjoyed directly or invested in legitimate business activities.
Indeed, bitcoin or cryptocurrency can be used as a new tool for money laundering, but the numbers are smaller because not all criminals want to access this method, many prefer conventional methods that are felt and are proven safe. In addition, criminals will definitely hide their crimes and feel ashamed of social sanctions so they tend to be reluctant to seek information. In addition, in the downstream sector, criminals will face KYC when exchanging their money into exchangers so that the potential for asset loss is still very large.