I dont realy know Add Disc 2 Disc feature I never use it EVER... ImgBurn is great the way it is, I dont think people would ever do somthing like that (people not on this forum) Disc to Disc is compromising the actual data... what is the disc get scratched or damaged you would need an Image of the disc the recopy it...
Bad things...
Discs cost alot of money these day especially Bluray...
Disc burns are not 100%
Discs require a dive to be played.
Good thing...
They are portable and small
The disc format works most of the time
ImgBurn is specail in it own way it would need such a feature as disc to disc copy when you can just do it already by creating a image file and burning it to a disc same time to do the process (maby a few seconds longer)