By that I mean that the sheer number of coins that are expected to buy pretty much anything at mid-to-high levels is so absurd that it makes the old imagery of treasure chests full of the stuff feel not only underwhelming but burdensome.
If 50 coins equal one imperial pound, as the rulebooks typically state, you could just about melt down and hammer out a house or a boat approximating the prices in the book for such things. It gets even sillier when magic items are so obscenely priced yet at the same time a typical adventuring party picks up so many of them that they could, materialistically speaking, pull a Mansa Munsa on any quasi-medieval economy if such items are really priced that highly where a hand-me-down magic protection ring could set up a peasant in endless luxury for life.
I don't try to fix all of that mess, but I do tend to use a house rule where coins have as much written buying power as 100x the listed prices for most things, and the coins found in a listed lair are reduced by to 1/100th of the listed values, which also keeps coppers, silvers, and electrum relevant a lot longer. As long as all the players remember the conversion tables and don't forget them in a way that fucks up the bookkeeping, it works pretty well.
How about the rest of you? :d20:
This was very much literal in old D&D, where Gold=XP.
Edit:
Also, I don't really think this part is entirely unreasonable? There are actually like, a couple of old-ass Spanish treasure-galleons that are still sitting on the floor of the ocean somewhere with gold coins in tow, I'm sure.
If a given society had some kind of spontaneous cataclysmic collapse, that didn't come about due to something like a Migration Period (which is not impossible due to this being a fantasy game), I could definitely see some weird old monarch's treasure vault kind of just getting left for the pilfering later on.