Additional productivity gains might be made by operating the "indoor farm" within dense urban areas and thus closer to the consumer, thereby removing transportation costs associated with a typical farm.
Those are overblown. Modern mega-scale logistics are stunningly efficient. Food shipped by freight-ship and truck are supposedly more efficient with less polution than a local farmer driving hir* produce to market in a car.
Sure, anything at industrial scale is going to me more efficient than a mom and pop operation. But with a system like this you've got scale and proximity. Instead of having a network of trucks delivering lettuce from California thousands of miles cross country, you can have a small fleet of trucks delivering lettuce within a 2 hour radius. Less spoilage, far less gas, and far less planning and logistics.
This could be huge in cities with abandoned/run down industrial districts that have been hard hit by globalization.
* I hate that term. So clumsy-sounding.