I have that table and really like it. I live in the desert, but for several years used an evaporative cooler during summer, which produces high humidity. No problem with the table at all. I know Atlanta can be muggy, but I would not coat it.
The top and edges are sealed, so if I were to coat the bottom, it would be with a good, pure paste wax, well polished. I wouldn't use any kind of liquid on it.