Not to be cynical about this approach, but having studied some of these concepts from a Mahayana Buddhist perspective, the idea of utilizing the perspective of Beginner's Mind to "grow your power" is a gross misappropriation and misunderstanding of the entire framework. In fact, within the traditions that originally conceived of these approaches, attachment to power, fame, and/or wealth is seen as the root cause of suffering and mental disenfranchisement and the very conceptualization that is to be let go [0].
Perhaps I need to look into this course a bit more to understand their approach but it seems that this is right in line with what many Buddhist scholars have worried - i.e., that these ancient traditions will be misunderstood and reformed in a way that may have wholly unhealthy effects on those who practice it.
[0] https://en.wikipedia.org/wiki/Four_Noble_Truths#Second_truth...