Actually it does. Here's how:
- Conversion from cash to bank account balances often carries a small 'change processing fee' with commercial banks. It's not big; but if you are depositing lots of tiny small change, many banks will charge you for the service. (esp. the other way around - getting cash out as coins, for giving change, etc.)
- Loss/theft - it's a lot easier for cash to go missing than it is for electronic payments. (plus costs for security for cash stored on premises)
- Going to the bank and depositing it regularly is going to cost anyway (salary for time spent, fuel, etc.)
I'd say the above equally match or exceed the 1-2.5% most merchant banks will charge for CC processing services. NFC pricing is generally the same amount. The fees charged by merchant banks for CC facilities are actually completely reasonable - there's some other aspects which hurt a bit more (90 clearance windows, chargebacks/fraud, etc); but the fees are perfectly fine.