The Chashmonoim were certainly not the first to mint coins. Although there are many proofs of earlier coins, the earliest example i can think of is Avrohom Ovinu who minted coins. See Bovo Kama 97b for details of what they looked like. An elderly couple on one side, and a young couple on the other side.
There is actually a halachic necessity for minted coins. Maaser Sheni can Revoi can only be redeemed onto minted coins. Nothing else. If the entire world turns to digital banking exclusively, we will be in big trouble. (Any country that stops will be in trouble, because you can only use local currency. but the issue is mainly in Eretz Yisroel where there is fruit with keduasha.)