When you create a product discount, you have the option to duplicate and hide that product; which means you can copy your product and apply the discount to it, without affecting the price of the original product. This feature is useful if you want to offer special discounts to certain people, without advertising the sale price on your site.
For example, you can use our Product Upsell app to create a buy one, get one 50% off deal. Obviously, you don't want to discount the original product's price because you don't want everyone to get the sale price, only those who qualify for the offer. This feature also removes the duplicate product from the site search results so you don't have to worry about people finding it who shouldn't.