Scratch-off labels have a removable layer over the information, you wish to keep hidden until the end-user of the product scratches off the coating material to see the information.
During promotional campaigns, this label provides an efficient conveyance of information e.g. QR code, lottery number, password, to the customer.
Additionally, many companies prefer scratch-off labels due to the authenticity concerns of their products.
Medicine, cosmetics, hair care products are another application of the label.