God is not concerned with trivialities of coinage. Indeed it is explicitly stated that `No one can serve two masters, for either he will hate the one and love the other; or else he will be devoted to one and despise the other. You can’t serve both God and Mammon.` (mammon meaning "riches"), which draws a clear distinction between those things that are of Godly import versus those that are merely earthly.

The point is that those items made in Caesar's image should be considered his property and reunited with him, whereas those items made in God's image (humanity) are God's property and should be reunited with Him.