Bolded a few points here. Why are there sudden smaller denominations than septims? Why are there suddenly other currencies? Yes, I know the Empire is crumbling, but it's not gone yet -- hence the whole Nordic civil war. Why are bank notes ("checks") being brought into being while the infrastructure that supports them crumbles? Why would anyone honour a piece of paper when the bank it is linked to could get sacked in the aftermath of the next battle? In Oblivion, a system of banks and notes of entitlement could have made sense. In Skyrim... not so much.
Daggerfall had weight, banks, and "checks", and it worked out well. It's only a matter how they balance it.
FO3 NV have wartime and "additional currencies", but there ammo has weight in "hard core mode". Works well too from what I've heard.
Realms of Arcania had denominated currencies (not sure about weight), and it worked out well. Never thought twice about it, was very natural.
Skyrim is said to have independent economies for each major town, which we can influence, so it kinda feels natural to me to bring more gameplay into it than simply having it there. Sounds to me like we're heading for economic warfare, which could be fun
So the story could be "endless years of war caused most gold reserves to be looted and new currencies had to be invented (more copper and silver mines, practically no gold mines), but the looters was subject to holdups and as such lost a few to road bandits (or whatever suits)".
Reason for denominations (and devalueing) are simple:
* War has made goods hard to come by. Folk rather trade goods than deal with coin, hence the devaluation. So a gold coin is a lot less than it used to be, and everything is also cheaper. Denomination means we can deal with other types of coins rather than selling for 0.03 gold which sounds horrible compared to 3S(ilver).
* For beggars, you typically only deal out copper. Earns you a bit of disposition but doesn't make you a god to them. Basic equipment, drinks, tips etc are also measured in copper.
* For advanced weaponry and armor (and amor?
), beds, and travel services, we're talking silver.
* For extremely rare equipment, horses, and houses, we're up in the gold business.
So silver crowns are now the "main currency" (read the "story" above) with copper bits to fill in the fractions (like most modern currencies). Gold is something kinda unique and rare, and hell, maybe some won't even trade in it?
Gold mining and gold as currency might be reintroduced as part of the main quest for all I care, acting as a driving force to complete the main quest to lessen the hassle for the player
Silver crowns are what you typically carry and "get by" with. If you choose to use copper is up to how cheap your character is. Being cheap have the cost of having more weight to carry around. Being generous buys you disposition for the "keep the change", rather than the silly "buy disposition" mechanic.
How fun is it to find a treasure chest with 56 gold in it? The treasure chest practically screams "loot me, please!", from miles away. It would be much more fun to have the treasure chest having only 56 silver crowns in it, and a couple of well hidden gold coins that was actually worth a bit, and rewarded the careful player. That would be the price for being casual about it. In Oblivion there are some neatly placed gold coins around, but what's the point when they're not really worth anything? It's easier to "hide" one gold septim than many. As they say "the best place to hide something is in plain sight"
Better to use light and night eye than to bee-line to the chest.
Gold should also weight more than silver, which in turn weights more than copper, *if* player likes "hard core mode". For casual play, they have zero weight, but denominations still have a purpose.
I referenced Realms of Arcania. See manual here:
http://www.lemonamiga.com/games/docs.php?id=1335
and observe the gameplay is A LOT deeper and A LOT less streamlined than any TES game, probably because they got away with simpler "screen code" back in those days. Best CRPG I ever played iirc.