Coupons are not inherently flawed in concept, but they can be misused by careless sellers. Often their perceived lack of efficiency is due to outside issues, including interference from Amazon algorithm changes or hijackers. When used for limited periods of time as a product promotion, coupons can be quite powerful in bringing revenue and attention to your brand on Amazon. However, sellers who keep heavy discounts active indefinitely are going to be subject to scrutiny by Amazon, questioning the legitimacy of the product offering.