But the top poster clearly demonstrates that there are significant costs in setting up such as system, much less that everybody has on their wallets or phones.

But the top poster clearly demonstrates that there are significant costs in setting up such as system, much less that everybody has on their wallets or phones. Even cash likely has a higher fee, if not from simple counting mistakes on many small transactions, then complexities like the safe, the risk to employees (insurance), the controller effectively managing the cash each day, the security of a bank truck, and more.