As the senators explained:

The EDGE Shelf helps Kroger gather and exploit sensitive consumer data. Through a partnership with Microsoft, Kroger plans to place cameras at its digital displays, which will use facial recognition tools to determine the gender and age of a customer captured on camera and present them with personalized offers and advertisements on the EDGE Shelf. EDGE will allow Kroger to use customer data to build personalized profiles of each customer... quickly updating and displaying the customer’s maximum willingness to pay on the digital price tag—a corporate profiteering capability that would be impossible using a mere paper price tag.

That's pretty fucked