My guess is China is standardizing and mass-producing coins, and molding is easier for quality control. Hammering is more straightforward for smaller-scale prod

My guess is China is standardizing and mass-producing coins, and molding is easier for quality control. Hammering is more straightforward for smaller-scale productions. Furthermore, China frequently forbids civilians to have weapons, while in Europe there are many weaponsmiths, and people are more familiar with this craftmanship. And is there is usually no face on coins in China. It's really nothing for some corner of the word to disappear after ages compared to making "kings" losing their nose and ears. The square-shaped hole in the center - people usually use a thread to string together the coins and use them as belts. It's much easier to have holes in the center if it is molded, though I'm not sure if the hole is the motivation of molding or the consequence of it.