There's another problem defeating the CIC on the console, as I was told, which is that some carts with some special chips in it, such as the SFX, work in a way that even if you defeat the chip the game won't load.
Normal games have a CIC in the cart so the console will allow the CPU to load the game, but these special games, having a processor in the cart itself, are also cic locked. If you prevent the CIC in the cart to properly communicate with the CIC in the console by defeating the latter, the CPU in the cart will be locked by the cart's CIC. In this case defeating the CIC is what prevents the game to load.
I can't confirm this, but makes perfect sense to me.