But that's exactly the point. The game of 20 questions is exponential as well. To uniquely identify a thing, the more specific you go, the level of precision needed to be unambiguous blows up. However, as a dialogue, you don't have to fully spec out every branch of the tree ahead of time. They ask a yes or no question and the ambiguity decreases exponentially for every question asked.
By having a dialogue, you can resolve only the ambiguities pertinent to the specific question at hand.
By having a dialogue, you can resolve only the ambiguities pertinent to the specific question at hand.