You are correct that the GEE file and the NC file are, essentially, the same. You will notice there is one additional line added to the front of the GEE file. This line adds two functions to the Iconic CNC that are not available to you if you do not convert the NC to a GEE.
1) The “Border” function. This allows the user to inspect the out limits of their program to insure that their material size matches.
2) The handheld controller will display the percentage of the project during the machining operation.
Some customers find these functions invaluable while others are not too concerned.
In either case the controller has no issue reading either format.