The original protective film can only protect the screen from scratches and pollutions for the period of time from delivery to use. It's not for regular protection for screen. And it won't work any more after using for a period of time. But sticker is different. Generally, sticker cover the whole product(generally, surface) to prevent dust and scratches. It has wear resistance and somewhat water proofness and quake proofness. But it also has disadvantages. There's a kind of specific glue on the it which makes it difficult to remove the sticker because some glue may remain on the surface of the products.
