But the value of commodities aren't fixed, but vary in both time and location. Much as taking a lump of gold and turning into a ring adds value to the gold, so does bringing the gold from the goldmine to the jeweler.

This just isn't true. Don't let Marx cloud your understanding of Smith.

Value is created when someone is willing to pay for something to get done, and that something gets done at a cost less than or equal to their willingness to pay. If somebody A is willing to pay for money to be moved, then as long as somebody B is there to move that money, then somebody B is likely generating value by doing so.