Cash is now for petty criminals only. For anything beyond car level of money you need involvement of politicians or high end criminals.
They tend to use gold and fake bank transactions BTW.
Just today there is a trial of the Turkish bank Halk Bank that was allegedly caught laundering money for Iran. High ranking Turkish and Iranian politicians are involved, the funds in form of gold were transferred using private jets and laundered through Dubai. The defense of the person who run the gold operations includes Rudy Giuliani. The things are at that level now.
Start digging from here if you want to know more: https://en.m.wikipedia.org/wiki/Reza_Zarrab
'M0' is cash. 'M1' are bytes in bank computers.
It's really not a big mental leap from USD that doesn't physically exist (which is 90% of USD) to crypto which doesn't physically exist.
Crime is gone now? What else are they going to use?
Crypto is used by less than 1% of the world. All crime uses "cash" relatively speaking.
*a lot of it is "digital" cash but still.