Why is 15 grams of silver coins in calligraphy art expensive in 218?

In p>218, 15 grams of silver coins for calligraphy art were less expensive to issue. Rare things are precious: The collection of gold and silver coins has always been adhering to the principle of "rare things are precious", and the "few but fine" varieties will surely become the objects sought after by gold and silver coin collectors. The maximum circulation of 15g rectangular silver coins in the gold and silver commemorative coin project of China Calligraphy Art (seal script) is 5, pieces, which is rare in the projects issued in recent years.