I thought this was an interesting article describing the issues surrounding the history and design of the U.S. Nickel or $0.05 piece.
While I doubt many go into this level of detail in their RPG monetary systems, I thought it might be of interest and perhaps even give someone some ideas when they develop a games currency. A lot of thought goes into a coin.
https://www.govexec.com/management/2018/06/nickels-cost-seven-cents-make-scientists-may-have-solution/149399/?oref=river
I'd fix the link if I were you.
And yes, coins, especially in the modern era, often have fascinating histories. I still have my grandfather's (b 1892) "half-dime."
What's wrong with the link?
You have no idea how much time I have spent working on currency for RPGs. The linked article was immensely interesting to me and I thank you for posting it.
For most of human history, coins served an important purpose for the transmission of propaganda.