Why would you go to the flash settings of your camera and disable flash firing? Just don’t use the flash I hear some say.
So here is why:
If you want to use the AF assist beam of your flash rather than the one you have on your camera but you don’t want to flash at all you can disable the flash firing.
Now you are able to use its assist beam without firing your flash by accident. It’s no rocket science yet somewhat confusing.
Have a great day shooting!