You’ve misunderstood. They’re not using this for inter-bank transfers. They’re using it for inter-branch/intra-bank communication. And most major banks - certainly the ones investing in blockchain - have hundreds to thousands of branches.
Not to mention signing+encryption and blockchain are not mutually exclusive. You can have signed and encrypted blocks on a chain
You’ve misunderstood. They’re not using this for inter-bank transfers. They’re using it for inter-branch/intra-bank communication. And most major banks - certainly the ones investing in blockchain - have hundreds to thousands of branches.
Not to mention signing+encryption and blockchain are not mutually exclusive. You can have signed and encrypted blocks on a chain