Board Thread:General Discussion/@comment-24310480-20140320023841/@comment-3974711-20140320160456

Because the Ultimatrix is a weapon, and that doesn't fit with Azmuth's vision for his creation (It wasn't even supposed to be called the Ultimatrix anyway, Albedo stole it before it was finished and refitted its function). Sure, Azmuth could have made the new Omnitrix and given it to someone else, leaving Ben with the Ultimatrix to keep. But he saw Ben as the only one worthy. Therefore, the defective watch had to go.