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.
Yes, people did that. But wouldn’t you do it evenly around the entire circumference of the coin? Why would you trim it to make the die perfectly off center on the blank?
Q: Why are so many ancients so far off center?
A: Because they knew that one day, thousands of years later, there would be collectors who cared about such things and they wanted to annoy them.
Beveled? How are our coins beveled?
Reeded - but not all of them. The precise manufacturing process DOES give them sharp corners.