>Speaking of which, debit cards are used extensively up here but I've never seen the attraction. Assuming one is fiscally disciplined enough to responsibly use credit cards, why would anyone want one?

As a wildly irresponsible credit card user, I am sure I am not qualified to answer...

- You can pay for your parking time in almost all parking spots in Lower Mainland with a Credit Card, but most of them do not take Debit, and with current prices here in Vancouver coins are not really an option :) I know that now there are more options, in particular in Vancouver I always use PayByPhone Application (which by the way, needs a credit card to set up the account), never used the phone call, but I guess you need a credit card too.
- Online shopping (this might be my irresponsible side speaking, maybe if I were responsible I should not be buying stuff - online or not) although in some places you can (now, not until recently) pay with Debit cards, paying with credit card is still the easiest way. You can also use Google Wallet or PayPal, but still the underlying payment mechanism is a credit card.
- From time to time you can get buy with 0% interest in monthly installments, you need to be careful with this thou, if you miss one payment they might hit you outrageous interest rates.
- Insurance when you pay for air tickets or rent cars in some places with some credit cards
- You can block payment if unsatisfied with your purchase, unlike the debit card
- Points / Discounts

I am sure there are more examples... And I am keeping with your premise of being fiscally disciplined, that means you pay the full balance of your CC before they hit you with the interests.