Okay, the thought experiment.

1- If banks can agree to trusted NANO addresses amongst themselves. They kinda setup a private blockchain on NANO for fiat exchange settlement.

2- Here's how it works. Fact: Settlement between banks are like an IOU. They provide liquidity on their own national currencies and demands from overseas. At the end of the month, the "balance" is tallied and topped up via forex intermediary banks.

3- Now what all these banks need to do is to agree to mRai values and peg them accordingly to the universal fiat (USD). For example 0.00000001NANO is 1 USD. Settlement via IOU is instantaneous as NANO is used as an ILP. At the end of the month, say BOJ is in a deficit of 0.3 Nano. He buys this back from national banks with fiat to buy off their surplus NANOs; to return the accounts back to the start state agreement of the liquidity each bank holds.

4- Since all transactions are recorded on the network, spam transactions from other non-agreed Nano accounts can be trawled and removed. The only issue here is DDOS

I think if we build the Nano protocol to include the function to have wallets being able to limit “receive” transactions via approved wallets only, we kinda build that "smart contract" layer. In that way, a private blockchain that is spam resistant.

Please do red team this thought experiment.

They already have trusted settlement layers.

All transactions go through the bank of international settlements (BIS) they won't be allowed to circumvent it or they'll lose their banking license.

Besides why on earth would they adopt something Colin works on at in his basement when they could just build their own with the army of coders they have?