The article fails to mention that it's not the Bitcoin blockchain this transfer system is riding on. It's a private blockchain, which has significant security drawbacks compared to the truly decentralized Bitcoin blockchain. Essentially it's another altcoin, created by some banks. Compared to a centralized database that services the same banks, it is much less efficient. Banks do not understand that the reason for the invention of a blockchain was to enable a decentralized currency, not for storing arbitrary data in it.
The whole concept of transferring fiat money via a blockchain is flawed. It's like transporting a horse buggy on a pickup truck, claiming that the horse buggy is the real thing.
ya.ya.yo!
It shouldn't really be a surprise that Visa isn't using Bitcoin's blockchain, but their own version of it instead. Whether it are banks, payment services such as Visa, the government, and so on, they will never make use of Bitcoin's blockchain. Simply because of the fact that it is decentralized. They want to be the alone ruler.