The smart ones manufacture error coins that sell for thousands of dollars - there were many made in the 1970s that combined Australian/New Zealand/Fijian obverses and reverses. Through the 2010s there has been another surge of such manufactured errors - generally one dollar coins made with 10c portraits (the 10c portrait is slightly smaller so it's a noticeable mistake).

I think the target was special limited-edition runs of coins which have above-denomination value. But yes, a lot of theft seems pointless.

A case in Brisbane involved a parking-meter attendant who had a gambling habit and sifted coins out of the street meters to put into slots. hundreds and thousands of them, over a career. If you steal below some threshold, the back end smarts (pre-digital) didn't "see" the discrepancy between meter state, and cash inputs. Probably some smart stats showed the anomoly, and then time series analysis showed when it cropped up.

All to pull a lever.