Why does one go through the stages of reckoning on the Day of Judgment when one already knows one's destiny beforehand?

Regarding the reason why a servant awaits on the Day of Judgment and goes through the stages of reckoning despite knowing their fate, it can be said:

Firstly: The terror of the Hour makes a person forget what they experienced in the Barzakh (interim period).

Secondly: What they witness on the Day of Judgment makes them yearn for salvation, so they argue on their own behalf.

Thirdly: The Day of Judgment is a day of reckoning, and it is necessary for Allah to establish proof against His creation and to reproach them with their sins until they acknowledge His justice.

Fourthly: It reveals the greatness of Allah's grace upon the believers and His justice with the disbelievers.

Fifthly: The terrors and stages serve as expiation for some of the people of faith.

Sixthly: It demonstrates the greatness of Allah Almighty and the truthfulness of His messengers.

Seventhly: It is the Day of Retribution among creatures.

Eighthly: Allah Almighty possesses perfect wisdom in honoring His allies and humiliating His enemies before all creation.