Yes. Banning cash and making every transaction public without bank secrecy is great anti money laundering measure But we are talking privacy. Privacy means also privacy from the vendor. It is almost impossible in iOS.

People ate already "laundering money" using cryptocurrencies, so banning cash won't fix anything. It will just make it easier for the government to take the taxes directly out of your account. And then invent some new taxes, until you will have to resort to "money laundering" yourself to make ends meet.