We had used our Canadian CC's at many shops in Cairns and Sydney, no problem.
As for taking train in Sydney, if you don't have opal card, you can use a CC that has Wave technology, and most CC's these days would have that. We took the train 2 nights ago, to the Circular Quay station. At the entry station turnstile we waved a CC, and at the Circular Quay station exit turnstile we waved the same CC. It automatically calculates your charge. So, if you don't have opal card, no problem to just use a CC.
But we'll probably use uber ourselves. This morning I checked the p