Because in this world, there are all kinds of wrathful and negative emotions or bad spirits, and sometimes they will harm you and other sentient beings, Dzambhala must take on such a wrathful and powerful form to protect us from these harmful spirits and negative karma. Especially, Dzambhala helps us minimize or decrease all misfortunes and obstacles and helps us increase all good fortune and happiness.
Patience is, for All as for Vipassana and as for this question, the Mother of Realisation. May All Beings be Freed of Suffering. May All Beings Attain Enlightement. Om Mani Padme Hum.