I find the appeal similar to the containerization technologies for computer software that have taken off recently. While having the binaries as part of the container is nice, the important part is that I can put my containers pretty much anywhere with minimal effort on my part and quickly/easily move if the current host tries charging too much. This basically is trying to do the same for housing.

Also you are not locked into the whims of the developers of the racks as much as you are with an apartment. Like making lots of noise at 3AM? Buy a pod with lots of sound insulation, same goes for someone who works night-shift and wants to sleep at 6PM on Saturday when everyone else is having a party.