It kinda depends on what aspect of the "Miner in a Box" you focus on. In my opinion, the whole immersion cooling stuff is squarely aimed at density (i.e. TH per square foot). The rest of the container business has been done by others and was aimed at simplification of installation and setup. Both of those have additional costs over and above the actual mining hardware. We've even seen a "Mining Trailer" that looked like it could easily be move in a day if the connections were right. While interesting, there is precious little value in making a substantial mining "operation" mobile to any significant degree. Yes it make the initial install easier, at a cost, but after that.
I focused on the immersion cooling aspect of this, and it seems fairly costly compared to a more "spread out" facility with lots of air flow. Pumps, radiators, and 3M NOVEC (or Flourinert), aren't cheap at all. They also have a long term run cost compared to fans and a more hospitable natural environment (e.g. a cool/cold climate).
Actually I think you are wrong. Exactly same density can be achieved with plain single loop water cooling, without the expensive two-phase fluid immersion cooling.
The target market is the buyer without enough engineering skills to design its own mining hardware based on mining chips individually mounted on small PCBs.
The actual strength of the two-phase immersion cooling is for example when you really have to use large PCBs, like e.g. CPU/GPU chips connected to large arrays of DRAM. With speed-of-light limitation you cannot design around that constraint and the 3D designs used in aircraft or missiles would be more expensive than the pricy immersion fluid.
Bitcoin mining has no such unusual engineering requirements. So their target market is somebody who really has no way of purchasing regular engineering skills but has large amounts of cash burning in their pockets. Only the usual suspects are left: money laundering for organized crime or some secret departments of small nation-state governments.