I actually once worked for a discount/coupon code website whose main feature was the ability to save offers. It had a low adoption rate. People who are aware that you can save money using coupon codes or partner links on the Internet also generally know that they can type "X free shipping coupon code" into Google and find what they're looking for (or better) again.
There's almost no user loyalty in the space, so creating an application people can go back to just so they can review the coupons they like is set up for failure on two accounts. This means the people behind the business ma not have done much market research. Or it may mean that they don't feel the need to cater to the customer, since they're not selling to them, but rather to the advertisers. So assuming that they had a solid business model and did the appropriate kind of research to make sure they would have clients and revenue, they probably have letters of intent and partnerships with a few advertisers who didn't crunch those kind of numbers, or trusted the perceived market expertise of this business.