Often container homes go above and beyond in their retrofits, and it would have been more effective to just build it conventionally. Both from a cost perspective and as a final result. If someone is happy with a simple container home, it really wouldn't be hard to build a similar box more conventionally.
I suspect the real issue at hand is that you're usually not allowed to build such a house, which is where the "tiny home on wheels" trend came about. Ignoring the part where an entire group of people seem to have forgotten that caravans exist, the "on wheels" part lets you build out-of-code homes and put them places you wouldn't be allowed to otherwise.
It really depends on a lot of factors though. What draws someone to a container home, is it the re-use and recycling? Is it the do-it-yourself nature of the project? If so, that's wicked, but I think we can probably work out ways to achieve those two things while also getting better and cheaper houses as the end result, if regulations would let you actually deploy such a house.
