If we can just see through the veil of delusion that clouds our minds, even for only a short time, then we can see our true nature, our Buddha nature which is luminous emptiness.
With this single deep insight we can see that our Buddha nature is our true self. This makes the path easier, it makes witnessing our true self something we can come to again and again. If we come to this realization, then our Buddha nature ceases to be something theoretical, a philosophy we adhere to, and becomes our real, direct experience.
This is what separates and individual on the path of Awakening from one that is not on the path.