Christ was God. He made man by talking to himself. Man sinned and angered him. God sent himself to earth to die himself to save mankind. He died and rose himself on the third day. Was all these necessary just to redeem a sinful man?
Christ's sacrifice was necessary in order to atone for the sins of humanity and reconcile humanity with God. Without Christ's sacrifice, humanity would remain separated from God (The Father) and unable to achieve salvation.
Christ's sacrifice was a demonstration of God's love and a powerful symbol of the lengths to which God would go to show His love for humanity.
From a theological perspective, many believe Christ's death was necessary for the forgiveness of sins and reconciliation between humanity and God, fulfilling prophetic and sacrificial elements in Christian doctrine.
Theological perspectives vary, but many Christians believe Christ's death was necessary for redemption and salvation fulfilling prophecies and demonstrating God's love and sacrifice for humanity's sins as outlined in the Bible.