Don’t some Central American countries like to use US dollars in cash, often preferred rather than their own currency? Mainly due to tourism but also probably some shadier stuff.

Right? A client of mine in Japan have new a hefty tip in USD. While I truly appreciated his kind gesture it was a pain in the ass for me to exchange it without paying for stupid exchange fees.

I don't think anyone here would want to receive physical USD.

I mean, that's just false. In a lot of countries with weak or unstable local currencies, big purchases like vehicles and real estate (sometimes even rent) are often done in USD to make sure the money keeps (most of) its value until you want to spend it again. I've seen it both in Africa and Asia. I've had to handle USD bills a lot even though I've never even stepped foot in the Americas.