You're using "true power" as a synonym for "omnipotence." Is limited power unreal? Don't you think Jeff Bezos, who has over a hundred billion dollars is truly more powerful than a homeless man? To say otherwise is to retreat to the idea that everything that appears to happen is only an illusion that doesn't contribute to knowledge. But we can indeed know that some people are really more powerful than others, even though no one on earth is all-powerful.
That knowledge is important because it's a condition of rectifying unjust forms of domination. Otherwise, why would the police seek to incarcerate criminals who try to overpower others such as by breaking and entering their homes, armed with loaded weapons? Should the police cease their enforcement of the law, because everything that appears to happen is only an illusion? That's where the rubber seems to meet the road with respect to mysticism.