Never heard of, or seen, the thing until now. Looks like a pretty cool bottom board and don’t see anything really wrong with it. It looks like this is a New Zealand invention? My only complaint would be the apparent inability to completely shut off the bottom screen in the winter. We have cold winters where I am. I don’t believe in a home with a open floor in the middle of winter. Other beeks will of course disagree. In more mild climates, I wouldn’t worry about it.