In the UK, £20 notes are the highest commonly used. That doesn't mean they get rid of cash. There are just very, very few cases where you need that much cash that £20 notes are impracticable.

There are valid reasons to have anonymity on the internet - plenty of them. It's really hard for me to grok the intrinsic value and human right of carrying a 200 note instead of two hundreds. If I'm gift giving, maybe, but frankly I can't stand getting hundreds as gifts, they're a pain to spend and just cause more work for me.

agree

I doubt most of these laws are ever intended to catch the big fish -- like in business, the big guys always require special handling to process. For criminals, the big guys should already be so far disassociated with the actual activity that you're not going to catch them with normal crimes. For example, Al Capone was famously trialed on tax evasion, rather than any of the innumerable crimes he committed but couldn't be processed for.

The actual law simply isn't that notable in these cases, because the big guys have enough money to figure out how to navigate it liability-free.

Which is also why the law only really applies to the poor -- with enough time and resources, there's always a workaround.

Good luck using one though in Brazil or Vietnam - they're illiquid relative to euros or dollars and therefore harder to launder.

"widely used currencies" can be read as "usd, eur, jpy, cny, gbp, cad", although chf is up there it seems.