And this is also why I've been encouraging--nay, expecting--people to do things like hold onto mined ores which (so far) are worth 2, 4, or 5 times as much as their weight. And why I even handed the players some nice lightweight etherstone bars when you were paid for your last adventure.
And why I keep saying "Please, please buy something! A sword weighs so much less than the loot you're carrying!"
It's like the humans down here are trading inanimate non-milk-producing cattle for all their goods. Perhaps this inversion of your expectations that "money should be easy" works better in my head than otherwise. But, just looking at modern fantasy games, if people really did lug around 1,000 solid gold coins to buy their medieval armor, they'd find their money pouches in the same situation.
To avoid carrying kilograms of dead weight, all it takes is using opal as an intermediary, buying something, and "getting on with it." But it's been difficult to cash out and spend the winnings in your wheelbarrows. That's surprised me: sure, sure, the characters wouldn't always agree how to divide the wealth, but can't somebody get some armor, somebody else get a weapon, a couple people say "pass," and call it good?
The overall goal is "please let's advance the game and make your characters more powerful instead of sitting around with all this loot." But if there's simply no way to agree across the team, then I'll change the rules to allow cashing out your goods in a way that'll save you on space. Deal?
(It's kinda contrived . . . but also precedented, and it'll tie into the plot.)