Economy is not trivial – as evidenced by its unstable course despite lots of smart people behind the wheel. In roleplaying games, the GM is burdened with being producer, trader, and single-handedly drafting currencies, tariffs and fiscal policies of Kingdoms and Empires on the spur of a moment.
It is well to do that unburdened by real-life economic sciences, otherwise it would prove a heavy burden. Ignorance is bliss.
And yet, it is interesting to look into the topic, if only to still the nagging questions about immense chests of gold and gems found in adventure locales.
I have spoken about it as a layman in the past, but there are those with more knowledge and more wisdom to offer.
This blog post here is a very interesting dive into the question of gold currencies through the centuries from Ancient Egypt via Rome up to Dungeons & Dragons.