There are some details in the body which are there simply for aesthetic reasons, and for no practical purpose--for example, the nipples of a man's chest, and the beard on his face, the latter being clearly for a masculine ornament, not for protection. (Augustine, City of God 22.24; trans. Bettenson)
The "Great Artist," as Augustine calls God in his final books of the City of God, made male nipples and beards as ornaments, for purely aesthetic purposes. Indeed, an artist as accomplished as God is not limited to practicalities.