For anyone else interested in the Payment Logic app, you can just sign up without being an existing customer. It's the blue "Payment Logic Personal" app in the app store.
Couple of things to note, yeah, it's BPAY only, and payments to the ATO are blocked (I guess so that all the business owners don't move from the more expensive platform). Sign up process is a bit coughbersome requiring at least 4 photos to be taken of you / ID / holding card etc, but got there in the end. Seems like it's basically just a cheaper version of Sniip. And, BPAY codes for credit cards are blocked, so you can't use AMEX to pay towards a credit card (just in case anyone had any ideas - no, it doesn't work, haha). Should be good for paying rates and water etc.
EDIT: Just like Sniip, BPAY to the main DEFT code is blocked.