In part this is because of the existence of Interac though. If Interac didn't exist it's possible they would feel they need to use VISA to not turn away too muc

In part this is because of the existence of Interac though. If Interac didn't exist it's possible they would feel they need to use VISA to not turn away too much membership. Having debit as a fallback means they can partner with whomever gives them favourable terms. I doubt Costco is paying Mastercard a % of the transaction the way most other retailers are. Despite it existing since the 80s, there's been constant pressure / lobbying to get rid of it.[1] [1]: https://www.theglobeandmail.com/report-on-business/interac-in-a-fight-for-its-life/article1364954/ https://www.theglobeandmail.com/report-on-business/interac-i...