We've already got a strong payment processing brand with Interac, it's used daily for millions of debit transactions, and supports all the features you'd expect (in Canada) from a payment card (tap, chip&pin). There's also the MasterCard Debit and Visa Debit branding which seem to bridge debit transactions to the MasterCard and Visa networks. And there's already Interac-capable terminals basically everywhere that Visa and MC are accepted.
My thought is that Interac should launch a credit card brand called "Interac Credit". The actual credit would be via the banks, just like it is with Visa and MC. Interac already has the relationships with merchants and banks to make this happen, and it has the mindshare with consumers to make it successful.