In a case your product is optimally protected. Dirt, moisture and other environmental influences can not harm the content. If your device or set is often used mobile, this is an important purchase argument for your customers. After all, they want to use the product for as long as possible. A simple cardboard box is not enough here. It will be broken after just a few times. With a case, you effectively reduce your complaint rate. Everything is and remains optimally secured.
By the way, your customer can conveniently store the product in the case. Space-saving stowed and protected from dust it waits for the next use.