Lots of people experiment with CO2 - from exhale bags and DIY yeast generators to burners and tanks. Some say they can see instant results even with cheap DIY methods.
The fact is that our plants can probably use more than is generally available. And plants use CO2 and light for photosynthesis. If they get light from the lights, then they need CO2. In theory, if you can deliver extra, the plants should use it. However, without a sealed and regulated environment, it is easy to waste most of the extra CO2 provide to plants.
CO2 is one of the "limiting factors" of plant growth. There are a number of these - some are listed above. While increasing any one might improve growth, doing this can also cause problems. (Think nutrient burn or heat stress.) To get best results of extras (like CO2), you have to keep all of these factors in balance as you raise them.
That's another way of saying what delvite said - more (better) light can balance with more CO2, more heat, etc.