I checked the prices. To be clear, I assume that we are talking about the "Economy Skycouch" programme. [1] Its better than just three economy sets because they lay down a small mattress that fills the whole seat area. It looks much more comfortable that trying to sleep across three regular economy seats! It looks like the prices are about 50-100% higher. That looks pretty reasonable to me, considering it is cheaper than buying the three economy seats. I wonder what the business analysis looked like for this offering. I guess they have some long-haul flights with low load factor, so they are looking to sell the empty seats and harvest some revenue.
[1] https://www.airnewzealand.co.jp/economy-skycouch