A common question asked regarding Confession is “Why should I confess to a Priest when I can pray directly to God?” Our God is a God of intercession. Throughout the Old and New Testaments God has used many Prophets and Angels to reveal Truth; God used sinful, imperfect men to write the Bible.
God could have easily made his voice heard to the entire world at once to communicate to humanity, but he didn’t do that, God loves his creation and uses his creatures to communicate his message. In the same fashion God established priesthood, imperfect men, used as instruments to convey his love and forgiveness.
Ultimately the reason why Catholics go to a Priest for confession is not due to the idea of any Pope or Priest, but the direction of Jesus Christ himself (John 20:21-23). We as Catholic Christians are simply following what Jesus has taught us.