Why am I asked for a credit card number when redeeming my Skywards Miles for free travel?

Credit card information is required in order to cover the government taxes and airport charges levied on all ticket purchases, including those purchased with Skywards Miles.

Why am I asked for a credit card number when redeeming my Skywards Miles for free travel?

What if I have difficulty redeeming my Skywards Miles for a Saver Reward on a high-demand flight?

Why am I asked for a credit card number when buying a flight reward with my Skywards Miles?