"Running a casino to launder illegal cash is so 1940s."
Global criminal activities generate trillions of dollars in profits. Estimates range from $2 trillion to $11 trillion (about 2-12% of the global GDP), but nobody really knows, since crooks don’t report their incomes. It’s safe to say that counterfeiting, drug sales, gun running, human trafficking and even illegal trade in wildlife generate a massive mountain of cash.
Trouble is, all that cash isn’t really fungible. Illegal cash has to be laundered before it can be used, that is, its illicit origin has to be hidden. And for that you need an accountant.