1 Lambert: Why would bandits hang out in badlands? Almost nobody ever travels here.
2 Alvissa: But the people who do travel through badlands generally carry valuable trade goods.
3 Lambert: So once in a while they ambush a well-armed caravan full of silk or spices or something. Surely it’d be easier to hang out in a city and steal gold?
4 Mordekai: Exactly what I’ve been thinking, my good friend.

Trade goods are a cool thing for adventurers to find as treasure. They're valuable, but they're not gold or other easily spendable currency. They need work to turn into coin.

So if you're running a fantasy roleplaying game, definitely consider setting up adventures where the heroes will be rewarded with things like silk or spices or tapestries or antique furniture or other stuff. Valuable treasure indeed... but make them figure out how to convert it into money.