If they'd make a 5gal one, I'd be interested

Just think about it. Lets say you have this big, awesome 50 gallon tropical tank. But the tankmates are not compatible with bettas, the current is too strong, the sheer amount of space would stress the betta, etc. However, we all know the benefits of large tanks; they have a more stable/consistent temperature, they can be cycled more easily, the pH and such are more likely to stay constant, and the larger surface area permits for better oxygenation. If you had a container that could be securely attached, with slats for circulation as that little thing had, a betta could be displayed in a community tank, with all of the benefits, but far fewer risks (the remaining ones I can think of would be stress or disease from tankmates). You could even put gravel in the bottom so long as its large-ish, and add some plants.
So, while that one is far too small, I do think that the
concept could have definate benefits for people who want the benefits of a big tank without stressing or endangering thier bettas (or other fish). I'd sign right up for one if they'd make it big enough, providing I actually
had a nice big community tank.