Visa settling dollar-denominated accounts with member banks seems like it must be very much a solved problem, that furthermore doesn’t need any kind of decentra

Visa settling dollar-denominated accounts with member banks seems like it must be very much a solved problem, that furthermore doesn’t need any kind of decentralized ledger or smart contract processing to accomplish. So either that’s exactly why it’s a bad idea, or my understanding of how this works today has huge gaps. (Which wouldn’t surprise me a bit.) Can you clarify what’s in this for Visa?