At first glance, it might not seem like the most practical invention ever devised, but that is only because Lift by Maurizio Cattelan is a minuature art exhibit and not a creation designed to serve as functional inter-building transportation.
Lift by Maurizio Cattelan was recently displayed at Galerie Emmanuel Perrotin in Paris, and it's not hard to see how even a small exhibit like this could generate a lot of positive buzz. Although the two tiny elevators don't actually move vertically, they do have doors that open and close as normal. On top of that, they also emit scaled-down versions of the sounds that you would hear from normal elevators.
To be honest, a part of me hopes that one day these things actually exist for real as it would be hilariously fun to send small items like pencils and messages to other floors of a building in a tiny elevator.