Here is one very important reason you should only drink naturally carbonated beer. When CO2 is added to beer, it nearly always has contamination. Only naturally carbonated beer is guaranteed to free of contaminates that can both ruin the taste and can even be toxic.
Most brewers purchase CO2 and add it the beer in the bright tank to ensure that the final product has the right levels of carbonation. In normal times, this is cheaper and easier. Recently the cost of CO2 has skyrocketed due to supply issues. The Jackson Dome was one of our largest suppliers of CO2 in the country, and it was recently discovered that other gases had contaminated the CO2. The vast supply of CO2 is now unusable for beverages, and has in part led to the CO2 crisis we now experience.
Besides underground reservoirs like the Jackson Dome, CO2 is also supplied by industrial processes, and is also subject to contamination. CO2 is a byproduct of creating ethanol or ammonia, and these tasty substances will be present in the CO2, albeit to a very small degree. Industrial made CO2 is 98-99% pure. But 1-2% ammonia or other gases can and certainly do affect the taste of your beer. We haven't even talked about the health effects of trace elements in commercial CO2, but that is for another day.
However there are ways to preserve the naturally occurring CO2 that results from the fermentation process. Göller Brewery, for example, has CO2 recapture technology as well as hermetically sealed tanks with Spunding valves. The Reinheitsgebot standard followed by traditional breweries means they cannot add CO2 because they cannot add any ingredients other than the 4 essential ingredients (water, barley, hops, yeast). This has insulated Göller from the CO2 shortages as well as contamination concerns.
So we have one more reason to source traditional German beer like Göller. It's natural from start to finish.