Coins, Treasure, and Experience
Coins in Weird Fantasy (like all the D&D clones) are large and heavy. This is a design choice as a pacing mechanic and challenge (one can only take so much gold from the dungeon) and for convenience, such as copper, silver, and gold working in denominations of ten.
DotW economy still operates within a base ten system: 100 copper = 10 silver = 1 gold. However, their value is increased, with silver being the primary currency for trade and experience. One silver piece = 1 experience point. Also, instead of 100 coins equalling one encumbrance point, now it takes 500 coins for +1 encumbrance. This is probably a little generous, but treasure in DotW will be mostly in coins and less in other forms of treasure, such as gems, jewelry, and items.
Treasure can also be cashed in for even more experience if the player uses it to further his fame and glory. Silver spent in this fashion, is worth an additional 1 experience point per silver coin spent. The goal is to speed up level increases, but to do it in a way that makes its mark in the world.