Apple's fee is NOT tiny. In fact, the fee (and the amount of information that Apple wants back from the banks) is exactly why we don't see Apple Pay rolling out over the planet. Banks in Canada and the UK and the rest of Europe cannot afford what the US banks are paying Apple. Not even close.
For example, in Canada, Interac charges its members 0.6 cents per transaction. Apple wants 0.5 cents per transaction. That would almost double the fee.
In Europe, interchange fees are capped at 0.23% for small NFC purchases. Giving Apple 0.15% of the purchase... over half of the collected fee... is simply not feasible.
In the UK, banks have also expressed worry about the amount of purchase data that Apple wants back.
No doubt with regards to Interac fees, and could care less for interact. I am more interested in using my Credit Cards with apple pay where 0.15% is a fair amount.