A redeemer was needed to save mankind. Who could fulfil that role? Only the Son of God who united His divine nature to a human nature could undertake such a task.
By becoming a man, and suffering and dying, Christ has defeated death and Satan, who is the most powerful fallen angel. Therefore Christ is superior to all the angels.
With man having fallen into an estate of sin and misery, God has taken the initiative to bring about the eternal salvation of many by providing a Redeemer.