Many countries, including those in the developing world, have had instant payments systems for years. They're very convenient, especially those that provide an "overlay" service (usually coming with a standardized app) that allows sending money to registered phone numbers, without dealing with bank account numbers.

Characteristically, the US version of instant payments seems half-assed. It's initially supported by only 35 banks (not including Citi and Bank of America). And it apparently does not provide a standardized overlay service. Many big financial stakeholders, including the credit card companies, no doubt view it as a threat and would be very happy if it does not catch on.