Banff in May or September is quiet enough to actually hear the wind through the pines and see turquoise lakes like Moraine without a wall of tourists in your way. Shoulder season means lower crowds, crisp air, and a better shot at scoring a decent place to stay near the trails.
A trip like this usually runs about $3200 for the week. Dropping that all at once hurts, so we need a plan to spread it out over time without paying extra just for borrowing.
That 0% window is a deadline, not free money. If you still have a balance left when the 18 months are up, regular interest kicks in on what is left over.