FWIW what GP wrote is not true of all banks in AU. I have made several transfers to new payids recently and they have all gone through immediately.

I've never experienced that, and as others have said, it's not true of all banks; most bill it as near-instant.

I think the biggest barrier to adoption for retail payments is a visibility issue - most people I've spoken to have no idea what Osko or PayID are.

It still totally undermines the system. I went two hours out of town to pickup a car, expecting to pay on the spot with PayID instantly, just like dozens of times before. It triggered the mysterious 24 hour waiting period of my or their bank (the biggest in Australia), and of course the sellers wouldn't let me take the car. Dozens of calls to the bank, escalations - nothing can be done.

I had to cancel the transaction (by lying and saying it was fraudulent), drove to the bank, withdrew the money in cash, and paid the good-old-fashioned way. headdesk.

PayID is useless as a payment system if you can't actually rely on it to make a payment in a timely manner.