https://treasury.gov.au/policy-topics/economy/black-economy/...
I've carried $2k USD in just $20s in my pocket across international borders, and had it been in $100s that would be the limit. But if I want to transfer even one million dollars that 100 trips. Or 100 pockets if I ignore the law. I own cargo pants, but even they don't have 100 pockets. And a billion? That's a thousand people each with a hundred pockets full of cash.
What I was saying is that mere logistics makes it hard to move a billion in cash.
So there's a natural prevention of moving large amounts of cash. It's not impossible, but "making it hard" was done on purpose. So cryptocurrencies are not "clever" for "fixing a problem". They're actually removing the amelioration to the problem.
E.g. try to regularly move billions in cash and see how long it'll take before you're busted for not reporting that you're doing that.
A billion bucks weighs a fucktonne.
I'm pro cash, anti cryptocurrency, because the comparison is absolutely ridiculous there's no contradiction.