@Seraphus @hyun50
Gold coins in ancient hellenic world would be about 2 grams in weight, up to 8 grams for heavy ones (so suuper small)
But first edition AD&D had gold coins (all coins actually) weighing in at 45 grams each... (2nd edition apparently reduced it to 9 grams per coin, in a nod to realism)
The coins in this story.. she had 2.6 million "coins" in a small bag that she could easily swing around.
Let's assume she's insanely strong for a princess and but it at 26 kg weight.
So one hundred "coins" would add up to one gram..
...I'd say it sounds like they've invented paper currency. (Or hyper-large denominations for coins, like "1000-gold coins" weighing 10 grams or less..