Paper currency encourages violent crime by making robbery pay off and drug dealing and illegal immigration profitable; by giving criminals an easy to use means of payment, Rogoff pointed out. In The Curse of Cash; he noted that the Swedish government greatly reduced the number of bank robberies by simply lowering the amount of cash in circulation, which made such crimes less profitable.
Ironically, this is a claim that is leveled at Bitcoin and other Cryptocurrencies, that they facilitate crime when it reality cash is by far the largest method or exchange for criminals.
They say more than half of the total worldwide value of US dollar cash is in $100 bills. This is pretty amazing, since you can easily spend a month in the US without ever seeing the $100 bill.
This points to the fact that US dollar cash has been a major facilitator of crime and corruption around the world for decades, if you want to use the language of the outraged Rogoff. Yet it's only recently that establishment figures started speaking against paper cash.
The real issue isn't crime. While criminal demand for dollar cash helped support the dollar in the past, since the 2008 crisis, the existence of cash has become a net negative for the system. That is because, over the last decade, deflation has been the main problem, and the elites would love to be able to use negative interest to force people to spend and lend. But the existence of cash defeats any system of negative interest.