Reserves are simply the liquidity that backs loans made within the system. Hence they must be created and tightly regulated by a truly sovereign government and lent only by a Public Banking structure that is not allowed to be corrupted by the desire to be profitable. Private Banking must be even more tightly restricted and regulated by sanctioning it to only aggregate priorly accumulated profits and savings without the ability to leverage such funds. Thus Banks/brokerages would not be able to leverage individual or commercial accounts, merely create bonds from such funds. The public Banking system, using money created by the sovereign money creating agency, would be able to leverage funds to invest/speculate with, but only for reputable, productive and non-destabilizing purposes.
Without such a tri-level banking/financial system the system is destabilized by greed, wild speculation and lack of ethical and adult responsible control.
The danger of excess reserves is wealthy individual and corporate access to them for illicit or wildly speculative purposes because of their creditability. Another very dangerous possibility is their availability and use for war funding. For instance, if the current monopoly on credit perceives their dominance being eroded or ended they may very likely have little compunction about starting a war that destroyed everyone’s productive capacity….and then of course they would be happy to lend us all the money to rebuild everything. This colossal waste and equally colossally unethical possibility must be avoided at all costs.
Of course quite aside from this re-working of the system, monetary grace/monetary gifting must also be integrated into the system in order to correct the systemic imbalance between a simultaneous excess of total costs and hence prices in ratio to total individual incomes created and actually spent. In addition, this imbalance is increasingly being added to by innovation and artificial intelligence as they reduce aggregate individual incomes.
This problem can only be resolved by an ongoing direct and supplementary gift of income granted by the sovereign monetary authority, a universal Dividend to the individual and by a gifting Discount by retail merchants to consumers which in turn is reciprocally gifted back to such merchants so that they can be whole on their overheads and margins.