I am wishywashy on details too sorry. There is a combination of your card (debit/credit[visa/mastercard]) and the merchants setup. I am not sure who processes the payment on the merchant/supplier side for EFTPOS vs credit.

So, if you have a Visa credit card, and the money comes from your credit account, like many, then it is clearly using Visa Paywave.

But historically, it was Visa and Mastercard that started it with "no pin required" as an opt-out thing(IE it was enabled for you by default), and their main market is credit. Most people just rolled with it.

Using the phone NFC however should give you more control I would think. But I honestly have never set it up.