In this example, the banking provides the service of a safe place to keep my money until I spend it. That's what I pay for, in the form account fees and the banks ability to leverage my saved money for their financial gain.

100% the opposite. Bankers make their money from the flows of cash streams. Putting my cash under a mattress or setting it on fire steals it out of the hands of your banking friends.

This may be a regional difference, but we make most of our money on fees. Cashflow isn't actually worth that much in the current economy.

Not that it matters though, I was trying to make use of the "common knowledge" that banks make money from your deposits, and that therefore you spending your money instead of depositing it in a negative return account is costing us potential revenue. I know that's not how banks make money, but it's the culturally accepted explanation for how banks make money.