speak for yourself, travel outside of US to see how well its implemented by even 3rd world countries like India. payment in seconds basically means you can use it (or a derivative) at PoS. that basically mean for vast majority of people who pay of their balances monthly, no income from visa transaction fees which can be 3%+ for small/mid retailers.
I'm speaking from 25 years of first-hand experience. The money doesn't need to move instantly at 99% of POS scenarios, just the understanding that the money will eventually move.
The parties who need fast money movement the most are criminals.