While what you said is true, you could never expect significant growth from corals because you would have to remove them from the small space.
Growing an underwater garden is what most reefers shoot for.
You can't have fish. Most reefers want to recreate a natural habitat for a saltwater creature.
viewing angles are very limited.
This is just a new breed of live water vase decoration, not fish keeping. Which is probably why I don't understand.
I am sure it is a great conversation piece.
I think you hit the nail on the head. It's cool that keeping a micro reef is working, but I guess I can't see the appeal unless you are looking for a hard to establish, fragile, difficult to maintain decoration. It is pretty, but a lot of work for a pretty vase.