The biggest issue I have with multiple currency's is ... Weight of coins. Not sure if any of you noticed, but your coinage weighs, and if you are playing a class with low strength that weight matters. If I had to deal with copper, silver, gold, and platinum... I would be trying to convert most of that to the higher denominations for weight savings alone. On the positive side it could bring up a nice RP issue... when some NPC says.. "I don't have enough change for that gold or platinum piece" and that's all you have to pay for it with. But that also could be really annoying for some players as well, as they have to micro manage their finances which can take away from game enjoyment.
The easy fix for this is to just make coins weightless (an automatic trait if they're changed from an inventory item to a character attribute).
Alternatively/in addition, automatic conversion solves this process. As ~50 coins weigh 1 lb, the max 9cp and 9sp would add negligible weight. You'd actually save on weight using this method by converting gold to platinum. Of course, this would prevent the bank-exchanging other posters have mentioned, but that type of mechanic is more sensible for regions with entirely different currencies, not just denominations of the same currency. See below:
I personally think that conversion should be handled via banks, because automatic conversion is a magical mechanic that sort of makes the whole point of having multiple denominations moot, and I think that having a coinpurse that you can use to contain all of your currency would be nice to have. So we disagree on a couple of minor things, but the most important thing is that the mechanic is implemented. Thanks for your response
My desire for cp & sp is mainly so that things could be priced at lower than 1gp (e.g., apples), allowing the game to give us more sensible low-level loot and have a slightly more sensible economy. I see where you're coming from, but most vendors can probably give change for anything but platinum pieces(?), so I feel that bank exchanges would be fairly redundant.
If the game doesn't have automatic conversion, then banks would definitely be useful for carrying capacity purposes. It'd be likely that treasure hoards found would have hundreds to thousands of each denomination. At this point we're getting close to the boundary between "fun immersive realism" and "tedious realism," but having to stop at a bank every 5-15 in-game hours wouldn't be
that troublesome.
Edit: Bags of holding solve the weight issue. Also, once you get a significant amount of gold (100+), copper pieces are effectively useless. So in most cases you could just not pick them up if you were near carrying capacity.
