This article discussing the pros and cons of different gasses with wine: Using Inert Gases in Winemaking - WineMakerMag.com, makes a seemingly valid point:
Carbon dioxide is unique among gases in its chemical behavior as well. While considered “inert” for some winemaking purposes, it actually undergoes a transformation in water (or wine). As CO2dissolves in water, some water molecules dissociate and interact with the gas molecules:
CO2 + H2O → H+ + HCO3–
As you will note, the reaction products include the presence hydrogen ion, H+. That, of course, is the marker for an acid solution and carbon dioxide is sometimes called carbonic acid when dissolved in water.
It is the reverse of this reaction, ions combining to form molecular CO2, that allows for the relatively slow bubbling of a carbonated beverage. By comparison, a completely inert gas such as nitrogen or argon will quickly bubble out of solution, leaving it flat. For some wine applications (as in sparkling wine), a high concentration of CO2 is desirable. Sometimes a moderate level of dissolved CO2 will provide a pleasant “lift” or brightness to the wine, even to the point of very light carbonation known as “petillant” or “crackling.” For still wines, however, only modest levels of CO2 are desirable and most of the gas from fermentation escapes in the months of aging prior to bottling. If you use carbon dioxide as your cellar “inert gas,” you may reintroduce an undesirably high level of dissolved CO2.
