The western church has managed to focus on the illustration of the denarius and miss the message. The point being made had nothing to do with the denarius and everything to do with man being created in God's image. The religious elite who were trying to trap Jesus would have recognized this immediately.
Whose image does the coin bear?
The silent question in light of Jesus' response: "Whose image do you bear?"
Render unto God what is God's.
Bam, they found themselves guilty before God, especially in light of the fact that they were abdicating to Rome, with no possibility of rebuttal.