Why did God [curse] is the ground for [our] sake?

Under the Father and Christ's direction, the human family participated in creation. This includes the nobel and great ones and maybe the not-so-nobel.  However, all things serve a purpose. God did need to create an oasis of the Garden for Adam and Eve amongst a violent world filled with briars, thorns, and predatory animals.  Adam amd Eve were tasked with "keeping" and preserving the garden which served as a protection.

Abraham 3:24 And there stood one among them that was like unto God, and he said unto those who were with him: We will go down, for there is space there, and we will take of these materials, and we will make an earth whereon these may dwell;

However, with the fall, Adam and Eve were cast out. The garden was not preserved, and they were then exposed/subjected to the thorns, briars, weeds, random violence and unfeeling cruelty of the universe-- for their good.  The purpose of life is a test to be subjected to adversity/suffering and see if we will still choose to be patient, obedient. loyal, valiant and devoted to God.  So the creations/works of the nobel and the less-nobel all serve Gods greater purposes and human-kinds greater good.