> Or, there's something called ACH which you can use to pay bills and businesses can use to send you money (e.g. paycheck deposits), but ordinary banking customers can't use ACH to send money to each other.

This is possible with some bill payment systems with some banks. You can send anyone money and it is either transferred via ACH or they send a physical check. The big banks generally don't support this.

I agree that ACH is broken because you can't use it to transfer money to anyone.