Stackable Promotions at Checkout: Why They Confuse Customers and How to Fix It

https://mike-wiki.win/index.php/Case_Study:_How_Mezzofy_NFC_Coupons_and_Mobile_Wallets_Broke_%E2%80%94_and_Why_Single-Use_Codes_Fixed_It

Promotion stacking - allowing multiple discounts, coupons, or incentives to apply to a single order - sounds like a straightforward way to drive conversions