As for the human monarchs, they need officers and other means because of their incapability to execute their rule alone by themselves. There is neither a resemblance nor a relation between the Divine officers and human ones.

Since most of the heedless and ignorant do not discern the beauty and wisdom behind events, they make wrong complaints and impertinent objections. So, in order to divert such complaints from God to them, causes are placed as an intervening veil (between people and God's acts). However, causes cannot be a consideration in the view of one who is able to see the real beauty and wisdom in events.

There is a parable to clarify this point:

The Angel of Death complained to God that His servants would complain of him for his taking souls. God answered him: "I will put illnesses and misfortunes between you and them so that they will complain of them, not of you."

In sum: the Dignity and Grandeur of God require the apparent causes both to prevent improper complaints and so that those who reason superficially should not see the hand of Power as directly related to certain seemingly insignificant or vile things and affairs. The Unity and Glory of God require at the same time that, in both the creation and disposition of things, the apparent causes have no part.

A note

Belief in God's Unity has two degrees:
One is believing superficially that God has no partners and the universe can belong to none other than Him. It is possible that one who has this degree of belief may be susceptible to certain deviations and obscurities in his understanding.