3D concrete printer - GIFs

[Elizabeth Greene]

Strange, no channels/place for insulation.

For the walls with the "wavy" infill or the re-bar reinforcement it wouldn't be difficult to do a long-nozzle expanding foam insulation to fill the cavities from the bottom of the wall to the top. That said, you're right. I'd guess that they have, as-built ignoring any funny business with e.g. styrofoam balls in the concrete mix, an R value of about 1.

I can't imagine what the structures are used for. In the second video I thought that maybe they were making trusses of some sort and just storing them by stacking. It seems a strange way of doing something without knowing more about the process.

These look like test pieces to me. I don't think they are meant for a practical use.