Carbon has many good qualities to it. At the same time it can also have a negative impact on your system depending on conditions. If you are using it because it is contained in the filter cartridge, don't sweat it. If you are adding it to your system - stop if you so desire. Carbon is not so essential as some would have you to believe.
Many of us do not use carbon and see it as an unnecessary expense. It depends alot on the quality of your water.If you have city water then it is unlikely to do you any good. It won't harm anything - it just isn't needed in most aquariums.
I do not use it unless it comes in a filter cartridge. I don't remove it if it does. When I change filter media, I mostly use poly fiber (floss). I remove the old material and put the plastic piece back in to use as a divider and then I fill the backside with floss.(Where the filter pad would have been) I can change about 20+ times for $3-4 instead of using the factory pads.
"Idiot" - nope, not even close. You were smart enough to ask.