The gas exchange that occurs primarily at the surface is what you must ensure is adequate. This is especially important in planted tanks, and I have personal observation of this. My tanks are relatively well planted, and this means that during daylight (if intense enough for the plant species) photosynthesis is occurring which is using CO2 and releasing oxygen into the water. During darkness (night), this ceases, and plants respire continually just as fish and many types of bacteria are doing, and this uses oxygen and releases CO2. CO2 is also released through the breakdown in organics in the substrate. At night CO2 levels will rise; this occurs in natural waters too, but in the close confines of a planted aquarium this can be very significant. Ensuring the filter is providing adequate surface disturbance to allow oxygen in and CO2 out is important for all fish.
Some years ago I noticed that my cories had faster respiration in the early morning. I increased the surface disturbance provided by the canister filter return spray bar so it rippled the surface at that end of the tank. Problem solved. Ever since, the respiration rate of the cories has been normal when the light first comes on.
Surface disturbance is the key issue, and airstones are not going to provide much of this by comparison.
The issue of driving off CO2 is debatable. I used to accept this, and it was general advice, to keep surface disturbance (and air stones) minimal. Seems that may not have been accurate advice, as many planted tank sources are now advocating quite the reverse. Given my own observations, where the plant growth has not been affected by the increase in surface disturbance but the fish have been helped...I would not worry much. Provided of course one is not creating a raging rapids but just ensuring decent surface disturbance.