Well, the ZBrush docs says it optimizes the order of the points (which essentially means nothing in terms of explanation lol).
What are the benefits? Does it actually decrease the file size? Make the mesh less laggy when you rotate it around the canvas while sculpting?
As far as I know, there are no benefits for the model inside ZBrush but optimizing the point order can ensure that your model transfers correctly to other 3D programs. Point order can affect how a model is rendered so in some circumstances your model might appear to have missing faces.