What about plumbing and water resistance to humidity in the bathroom?
The problem is the same irrespective of how the house is built. You need holes for pipes and holes for an extractor fan. The bonus here is that 3D printed surfaces mean you don’t need to drill out material to make the holes.
really, though, you can finish them like any other house; there's nothing special about the kitchen, bathroom, or walls that precludes it.
aside from the striping, i imagine there's not that much different about building internal structures into a house like this than there is into more traditional rammed earth housing.