Milarepa is a Tibetan historical character roughly comparable to Jesus.
His story helps explain how Tibetan Buddhism has acquired such a powerful mystical component. Briefly, Milarepa was a terrorist in his younger days. He was all around evil. In his later life he touched the opposite extreme.
The important point about his life is the balance. Some people would like to control their, and others', destinies so there is only good. The truth is that you can only observe good and evil, you cannot choose which to be. If you "choose" to be good you will be a fraud. Acting good and being good are not similar.
Further, a person cannot be good or evil. They are both, to equal degrees. For some, in mundane life, good and evil are opponents that battle until one wins. However, in mystical traditions everywhere, evil is a precursor to good, just as ignorance is a precursor to knowledge. So when a person is "good" in a true sense, it is because they had first the evil then that evil provided a space for a comparable good. The false good that is sold by some religious people is notable only for its shallowness, its pretense. It judges but does not understand.
The focus on practicalities in Tibetan mysticism is certainly due in part to the difficulties of life in the Himalayas. Any advantage that increases survival is interesting.
Tibetan esoteric learning is also analogous to Western science.
The tragedy to humanity of any potential loss of this resource should not be ignored.
There are also some excellent films about Milarepa's life.