Another thing to remember about Canada is that we don't use cash as much as the US. Cash accounts for less than half (44%), by volume, of transactions in Canada. I'm not sure what the split between Interac (direct debit from your bank account) and credit cards is, but the mechanics of the transaction are almost identical - Interac prompts you for an account to pay from, both prompt for your PIN.

When you pay for something electronically, the rounding rules don't apply. If my bill comes to $10.42, I can save two cents by paying cash thanks to the rounding rules. But if it comes to $10.98, I save two cents by paying electronically.