That was one of the things that XI did very well, too. Rewards that aren't meaningful aren't rewards, and it does a lot for engagement to have players set goals for their rewards that they can accomplish. When you just hand it out like Halloween candy, it's forgotten just as fast.
600g for 3 silk thread?
No no no you traded in the crawler calculus for the gil. (And the NPC gave you cash for them because the crawlers were eating all the dhalmel chow.)
You saved silk threads til you had a stack, which then sold for 5000-10000 gil on the AH to desperate cloth crafters.
Yeah I figured that out after I'd traded a few stacks to the NPC