It's the Amazon model the French were fighting against.

Amazon killed a lot of retail by offering cheap / below cost shipping and at cost goods to attract customers and squeeze out brick and mortar retailers. Now that Amazon has hooked people and retailers have gone out of business, Amazon raised prices. The deals arent there and the products are more expensive.

These dark stores would have undercut real grocery stores until there were far fewer physical stores. Then, once people relied on them, they would have jacked up the delivery fees, reduced the variety of goods and charged as much as an in person grocery used to.