Why treating incentives as channel extras is breaking checkout — and why sub-50ms decisions matter

https://www.bookmarkpage.win/how-a-200m-retailer-overhauled-stackable-promotions-to-cut-checkout-confusion-by-80

Most engineering teams treat incentives — coupons, loyalty redemptions, targeted discounts — as per-channel add-ons. Marketing owns emails, commerce owns site, apps get their own rules