For an international supermarket chain, we created an in store shopping app. With the app, customers can do the same as they would be able to do with a self scan device (and more). Scan an article before you put it in your basket and when you are done,  pay at a payment booth or just at a regular cashier. A convenient form of self service that offers service to the customer with a significantly lower investment need for the retailer compared to a hardware self scan solution.