The thing about locking up all of your merchandise behind glass is your customers can’t actually buy it. Well, they can if you have employees who give a damn about helping a customer. This Walgreens in Brooklyn does not have those kind of employees.
Self check-out is great if, say, you’ve got one of those supermarkets where the teenaged clerks hate you for choosing their lane and spend more time talking to each other than scanning your items. It’s not so great if you force all of your customers to use the system because you’ve decided to close down every other human-powered lane but one.