The emphasis on A) the barges will be moved in/out of the lagoon everyday, and B) the hexagonal setup means the show looks the same no matter where you are around the lagoon, is pretty funny. About as close as you're going to get to Disney saying, "Fine, we heard you, you didn't like the Harmonious barges. We didn't do that this time!"
But the nesting of the smaller barges into the larger ones, and how they can move and store them as one unit, is smart engineering. Hopefully the show's content matches the care that was put into the infrastructure design.