If a user searches for a product on your website and doesn't find it, he will go to another website that sells the product and buy it there. You will lose the opportunity to sell to him. You will even lose the sale of the product available in your store, since it is easy for him to buy everything from a single store.
With FindAnyway, you can give sufficient choice to your users to buy all products from your store. When the user searches for a product not available in your store, we find it from Amazon and show it in the search results so that he can make the purchase directly on your website. More choices for your users, and more sales for you.