I pay people globally through HSBC all the time. Works instantly.
I never understand this argument anyway. If you can't send funds instantly that isn't because the currently itself can't be transferred instantly - it's because for whatever reason you don't have access to a provider that will provide that service. That's a separate problem and can be solved without having to build an entirely new currency / financial system.
The reason we have cash is (1) we used to not have widespread electronic instant settlement systems and (2) because you still generally need some type of physical fallback system because we energy sources and communications networks aren't always up.
Bitcoin is bad at 1 - 7 transactions per second (something something lightning network), and completely fails at (2) because it can't settle transactions without the internet, and electricity.
That may be what you think of as the core reason for cash to exist, but you shouldn't speak for others, who may see the privacy as a more relevant upside.
