Americans manage a further level of confusion by referring to the "pound sign" as #, rather than £, which isn't in US-ASCII nor on the US-102 keyboard layout.
Good point, historically British currency wasn't decimal. "Decimal Day" in which the pound was divided into 100 new pennies happened just a few years before I was born. So I grew up with the physical coins often still denominated in shillings or old (pre-decimal) pence, but knowing (since it was true from before I'd been born) what their actual value was in the only currency system I had ever experienced, so e.g. I see a shilling, I know it's actually 5 new pence. By the time I was a teenager there were very few actual shillings in circulation and lots of new 5p coins and then the coins were deliberately reduced in size anyway, obviously if you still had a shilling it was now obsolete because it was the wrong size.
My mother grew up with the currency around her not being decimal but by her teens the government were explicitly warning that this was coming and she learned that e.g. a pound has 100 new pence in school ready for a career where this would soon go from theory to practice, when she finished school the poster campaigns were running IIRC.