It predicts which move is optimal.
Maybe it would be useful to define terms, to make things more clear.
If you have a time-process X, and t observations from this process, a predictor comes up with a prediction as to what X_t+1 will be.
On the other hand, given a utility function f() on a series of possible outcomes Y from t+1 to infinity, a decision maker finds the best Y_t+1 to choose to maximize the utility function.
Note that the definition of these two things is not the same: a predictor is concerned about the past and immediate present, whereas a decision maker is concerned with the future.
a predictor comes up with a prediction as to what X_t+1 will be
This "t+1" might be "t+X". Results for a large X may be very bad. So as results for "t+1" may be bad. Still he do his best predictions.
whereas a decision maker is concerned with the future
He predicts the best decision, which can be taken.
Yann LeCun, now of Facebook, was interviewed by The Register. It is interesting that his view of AI is apparently that of a prediction tool:
"In some ways you could say intelligence is all about prediction," he explained. "What you can identify in intelligence is it can predict what is going to happen in the world with more accuracy and more time horizon than others."
rather than of a world optimizer. This is not very surprising, given his background in handwriting and image recognition. This "AI as intelligence augmentation" view appears to be prevalent among the AI researchers in general.