Noise Reduction with stacking allows you to improve the SNR (Signal to Noise ratio) of your imagery by stacking together multiple shots of the same subject and "averaging" out the noise. Since the subject remains consistent from shot to shot but noise is random, it can be removed efficiently without compromising the clarity of the subject.
This technique is beneficial for static scenes, especially in low light photography where noise is often unavoidable, either due to high ISO values or long exposures.
Here are a few things to consider when shooting.