Just FYI you can look up stuff like this at no cost. It's not even close to being true. A Canadian polymer banknote costs about 20 cents to manufacture and the smallest denomination is $5. Coins cost a few cents to make (even $2 ones). It's just the penny that lost so much of its value over time that it costs more to make than its worth.
Well except that if you are doing it with cards you have to worry about being skimmed. Here in Canada they have chip and pin but guess who gets stung with purchases 4 out of 5 times when it happens because it doesn't ask for the pin all the time.
Now if you do it through a smartwatch, phone, or some other device that can't be skimmed when it isn't being used, then that is the way to do it.