Earlier this week, in Brooklyn, near the waterfront, Amazon opened what looks from the outside like a typical Whole Foods store. It isn’t open to the public, however; it’s a new fulfillment center.

It’s still a niche trend — retail properties being converted to industrial use. While 14 million square feet has been converted in recent years, it’s a drop in the bucket compared with the 14.5 billion square feet of industrial real estate in the U.S.