The coin pouch is useful because, without it, a player can carry only 100,000 gold before they begin dropping coins. A coin pouch adds an additional 100,000 gold to this limit.
If the coin pouch is in a player's inventory, gold will be transferred to it. The amount in possession will be enclosed in parentheses. Should the player drop the pouch while carrying an amount of gold over 100,000, they will begin dropping coins as they walk.