Why is Murgo Gold used as a currency?

Question

Murgo Gold is used as currency by the Grolims to trade (or at least act) and pay their agent. The thing that confuses me the most is that how this currency is counted as gold equivalent when it's nothing like it. Murgo gold is:

• Blood red compared to actual gold.

• Quite abundant compared to actual gold. Pawn of Prophecy "The mines of Cthol Murgos and Gargo Nadra are endless, and the Grolims have more gold at their disposal than you could even imagine."

• Although not widely known, almost all figures of power seem to know that the Murgo Gold have corrupting influence.

So why is Murgo Gold used as a currency?

Answer 1

Why is anything used as a currency?

Because it is accepted as a medium of exchange. People have desire to hoard regular gold. A gold that makes you want to have more of it magically? Why won't you want to own it and trade goods for it?

Especially if it is not well known property of it.

As an aside, people made green paint before and it sold well, because it was the color green they have never seen before. They didn't know it was extremely poisonous. It was called Scheele's Green.

They also played with uranium and plutonium (making even glow in the dark toothpaste and watches!) before it was discovered that those cause cancer.

Humans are willing to trade a lot of things for a high price because they like it. A thing that makes you magically want you to have more of it will fetch quite a high price. Think about highly addictive psychoactive drugs.