I'm not sure about your conclusion here. If we don't repeat the letter then we're going to have information about another letter, which we don't want.

Words with repeated letters are a great strategy, as long as you know or strongly suspect the letter isn't in the target word, and the letter is rare so eliminating it doesn't eliminate much.

They are a fantastic strategy, though if one happens to rob you of a lot of remaining words, you should undo it.