How could the Romans be so good at engraving but so bad at punching out the coins?
Maybe the size has something to do with it. They didn’t have magnifying glasses yet..................
I think that’s because people would shave just a little bit of the edge off, save the gold, then do it every time a coin passed through their hands. Soon they had a small stash of “extra” gold.
That’s why the edges of modern coins are beveled, so you can see if someone has shaved off metal.
I don’t think they were punched. I belive a blob of molten gold was dropped into a mold, then “struck” with a top die before it hardened completely. That’s also why they are off center and not always perfectly round.