Another thought: How would you actually deal with banks? Private banks are of course a bad thing, but would cooperative banks be optimal? Those would still need positive interest rates, but if you think about it, interest rates are actually harmful. Interest rates increase when risk is higher, but thereby the risk goes up even more. Actually, one doesn't need interest rates to keep people from taking big loans they can not pay back - a hard bankruptcy will do the job. So, interest rates serve no purpose at all on credit taking side. So, it would be much better to have banking in the hand of the state. Then, you do not even need the savings of the people to give credits - collecting them at banks then only serves the purpose of having some overview, and people will still have most of their money on bank accounts because it is easier to store the money there and banks make paying easier.
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