Well, assuming that you have a cell phone that matches the Ouya in power. And that you like having to tether it to your TV every time you want to play a game.
Also, while there's no fundamental reason why developers couldn't release a game that is optimized for controller play on a TV that runs on your standard Android phone, in practice that is not what has happened. They seem to be hoping to change that by allowing Ouya games to run on other Android platforms, but that's still on the horizon.
There were some serious mistakes made in the design and marketing for Ouya, but I like mine and have bought a fair number of games. It's not "redundant."