Back in the day, when megadungeons were not yet considered something ‘nostalgic,’ most treasure hordes were generated randomly. Sometimes the book would tell you that each bandit might have 1-8 silver pieces (so if you slaughtered or robbed 5 bandits, you could expect to gather 5-40 silver for your trouble). But in many cases, you were given a treasure type that may or may not have involved , for example, a 50% chance of 1,000-10,000 copper, a 25% chance of 1,000-8,000 silver, a 10% chance of 1,000 to 4,000 gold and a 25% chance of 3 miscellaneous magic items + 1 scroll. Of course, rolling up the treasure the way Gygax (or Dr. Eric J. Holmes) told you to meant you ended up with huge numbers, usually multiples of 100 or 1000, of the same type of coin. Obviously unrealistic. AFAIK, in medieval and ancient times there were no places where a ‘single standard currency’ was in use (assuming what I have read on the subject is true). Roman and Greek coins continued to be used by all nations long after the Romans and Greeks had fallen from power. Merchants used scales to count coins; since they were handling so many different denominations, you didn’t want to convert cistercii and drachmas and silver marks and god knows what else into a single value, you would have just thrown a bunch of silver coins on the scale and made a judgement as to how much was ‘enough’ by the weight. So, if ancient times are our model, a pile of 764 copper pieces, 357 silver pieces and 35 gold pieces (plus the odd pair of elven boots or whatnot) is still unrealistic because it assumes that all the coins of a given metal are all the same value (as well as the same size and weight).
Where can our pursuit of greater realism in treasure hordes end? I see several options. Option 1 is to make hoards more complicated, with coins of different nations, weights, etc., and then extrapolating some ‘central universal value’ from that. Option 2 is to stick with the copper pieces, silver pieces, gold pieces, etc., and avoid big, fat, round & exact numbers (the players don’t find a heap of 2,000 copper pieces, perhaps they find a mix of different coppers, silver and gold that add up to somewhere around 2,000 copper pieces in value) or option 3: “You find 2,000 copper coins.” Call me crazy, but when I look at the options, number 3 doesn’t seem to bad anymore.
In addition, in all the games I have been involved in, I don’t remember players taking the time to say they counted the coins. We have made jokes about how we could glance at a chest and see that there were 4,000 gold coins in it even though I have no idea how many pennies are in the change jar on my dresser that I walk past at least twice a day, but that was always just a part of the fun. If one needs to rationalize, maybe the “2,000 cps” is just a simplified value for the hoard to make book keeping easier.
If I remember right, back in the day, no self-respecting dungeoneer bothered to pick up copper coins anyway. The weight-to-value ratio meant picking up used orc spears and goblin daggers was usually more profitable than picking up copper coins. By the time we had a level or two under our belts, we weren’t bothering with silver coins any more either. We left the silver and copper for the linkboys and henchmen to squabble over and went straight for the magic items first, the gems and jewelry next, the platinum third and the gold last. The rest of the coins were worth less than the iron rations the adventurer would have to throw away in order to fit them in his backpack.