I'll choose the store where I can grab what I want and walk out over the store where I have to wait in a dumb ass line while the cashier yells for a price check and the customer in front of me can't remember her PIN so slowly counts out nickels and quarters.
It's a massive competitive advantage far beyond whatever data they get by watching me roam the store.
The primary benefit is access to a lot better data about shoppers, not a better customer experience.