

You know how you can only withdraw a certain amount of money from an ATM even if you have more in your account and need it in cash?
That’s because of laws against money laundering and terror financing. The gist of it is that criminals and terrorists will finance/get cash out of their activities through using a bunch of middle men/fronts, cash and other ways to obfuscate the origin/destination of the money.

Yes and no, it moves the goal post and makes it harder for some criminals/terrorists to launder money. But organized crime is one of the largest business sectors in the world, so many have large incentives to get around the rules.
It’s helpful to think of crime as a (or many separate) business sector(s) in this context, because at large scale criminals can benefit from much of the economic infrastructure that is required for legitimate international businesses, particularly modern businesses that sell things that don’t cost much/anything to produce (doesn’t have a fixed profit margin), such as subscriptions, streaming or intellectual property (e.g. music or games downloads).
Not long ago the circulation of this dirty money was a staple of many parts of the established financial system (see the Wachovia cartel scandal as an example). Today’s rules and crackdowns after the 2008 financial crisis has changed that somewhat.