You make it sound like the other $85 that the bank got sits in a vault somewhere, extracted from the economy and hoarded in a stockpile. Actually the banks have their own costs (e.g. salaries) and much of the money is further invested. In fact, the natural state is to keep so little cash on hand that Dodd-Frank forced the banks to hoard more than they otherwise were inclined to.

Yes I've oversimplifying a lot of differences (payments infrastructure vs. investment banking, for one) but the point remains. I do think that day-to-day realtime debit-style payments should be a publicly-operated, minimal-or-zero-fee commodity rather than a massive source of rent, but having access to electronic payments for consumer retail is literally responsible for trillions of dollars more economic activity than you would see if we went back to cash-only.