Jeff Carlsen
Adventurer
No, I believe I didn't miss the point. A silver standard is pointless. Gold pieces are already a fine standard and there is zero reason to have two sets of currencies in the game.
The silver standard may not be to your taste, but it isn't pointless, for the same reason that there are more than zero reasons to have multiple currencies.
Gold is rare and extremely valuable. Today, a single troy ounce gold coin is worth $1700. Now, you may not care if your fantasy world holds true to this, but many of us do. We want gold to be rare and highly valuable. It's treasure, afterall. We want an every-day currency that covers most adventuring needs. Appeasing these desires is a considerable reason.
The other reason is weight. Unless you don't even consider the weight of coins, which is significant playstyle decision.