They seem to have mixed up horizontal and vertical, and if they did, then my reading is that they're saying the cost of the extra floor space (and the loss of the "shelf" space on top of the fridge) when using a chest fridge makes the economics unfavourable for people in dense urban areas, even with the energy savings.

At least, I'm hoping that's what they meant. If they really meant horizontal and vertical in the way they used it then I've got no idea either.