It looks like an interesting product. I think I've seen a material that was similar years ago. It was an ultra light aerated concrete. It was something like 1/5 to 1/3 as light as normal concrete. Picking up the blocks was really weird. It felt closer to styrofoam than concrete, and it floated in water. It made a very similar sound when the blocks rubbed up against each other, and apparently it had an excellent r-value.

My issue with this system is that it looks like the foundation would have to be basically atomically flat for this system to fit up. I'm sure you could do it, but it's probably a LOT more work than they're letting on in the video. Mortar isn't just for joining two pieces together, it's a gap filler that makes up for misalignment.