[ForHackernews]

It doesn't even need to be that fast, as long as it's secure and credible. Stock trades in the US happen "instantly" (or near enough), but actual settlement takes place two or three days later.

The cryptocurrency people are hung up on the idea of "fast, irreversible payments" (that settle at the same time as the trade) because they desperately want a trustless, digital equivalent of cash for political reasons.

But for merchants and mainstream users, a fair, trustworthy payment system run by known intermediaries would be much better. It can be slow, as long as merchants know they'll get their money in some reasonable timeframe. The problem is that the Visa/Mastercard duopoly makes it hard to innovate.

It's possible FedNow will fix this https://en.wikipedia.org/wiki/FedNow