This is an interesting proposal. Private banks have two very important functions in society: they provide the infrastructure for the payment system and they control credit. This proposal would disentangle those functions making, I think, a more robust financial infrastructure. The payment system is, by its characteristics, a natural monopoly, and it's so important that makes sense that it become public. If that was t…
“Robust banking system” is inherently tied to reserve ratios, or having the deposits on hand to cover the loans you’re writing.
A bank that only writes loans and doesn’t have deposits is the opposite of robust. If any bank gets to do this it would be the central bank. Payment facilitation is less of a superpower and can be more safely entrusted to the private sector.