This was the second part of the atonement showing, not sacrifice, but the effect of sacrifice, and explaining what becomes of sin after the sacrifice has been made and accepted and the blood has been presented in the veil. The people watched as the goat was led to spot far away - a striking portrayal of God's promise to remove their sins from them. All our sins are taken away, and taken far away. Read 1 Jn. The whole sin offering had to be burned including the offal or dung which more strikingly set forth the impurity of the sin connected with the sin offering.
Sin is like manure to be burned up.
Throughout history most men have a certain motivation to work, especially for food or for money. But in the OT God told them sometimes not to work, to stop their work. He was saying there is one thing even more important than work. God is more important than work. And our relationship with God.