system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can’t you spend dirty money like regular, untraceable cash? Why does it have to be put into a bank?

In other words, why does the money have to be laundered? Couldn’t you just pay for everything using physical cash?
gpt
You can, as long as it's "everyday people" sums. You don't have to launder $2K. But if it's millions, people will get suspicious about how you can afford the stuff you buy, no matter how you buy it. And then you better have a plausible explanation, which is exactly what laundering aims to create.