The best brunch spots and caterers book up weeks before the shower. You want to lock in the vendor at least a month out to make sure the date is yours and the menu is set. This is a deadline purchase, so the earlier we get the paperwork signed, the less we have to worry about last-minute substitutions.
Paying $800 all at once is a big lift for a single morning. We can use a specific card window to break that total into smaller, manageable monthly chunks while we focus on the guest list.
The intro window is a firm deadline, not free money. If you still have a balance on the card after the 15 months, the standard interest rate will apply to whatever is left, making that brunch much more expensive than you planned.