This predates the 'Apps' by a good margin. Safeway used to do this a decade (or more?) ago. All the prices in shelves are artificially jacked up. Only if you use their 'card' you got real prices at checkout.

I refused to get their card and stopped shopping there.

Requiring the app also disadvantages the elderly, particularly with dementia, who can't operate a smartphone. In theory, the cashier is supposed to allow anyone to access the discount on request but, in practice, I've seen them get rather unfriendly, even to the elderly, when they have to go through the process of manually punching in the discount.