No, the vehicle auths with the EV charging station and my credit card is charged when the charge is complete. No phone, rfid tag, or app required.
Yes, 20amp 120V outlets are great for long term parking, like airports. Those can be unmetered. Anything else would be a level 3 fast charger like a supercharger, where you have to pay to cover the demand charges of 120kw-250kw current delivery in a short period of time (15-30 minutes). Remember, most people will charge overnight at home.
The electricity is the cheapest component, as you mention. You’re really just paying for the delivery infra. Regarding the idle electrical costs of signaling systems for charging stations, it’s minimal.