Interesting question.
One analysis here:
https://www.cato.org/cato-journal/fall-2021/covid-19-coin-shortage-causes-responses-lessons
We stopped using coins with covid. they are sitting in pockets and couches?
After reading the article, now I’m wondering if it was part of a planned push to virtual cash - which is more controllable - as well as a swipe to small, independent businesses.