Everyone keeps mentioning distance as a reason that guns are important....if you read stories of self-defense with firearms, almost all of them take place at close range, and they often begin with the victim being struck or grabbed by their attacker, before they draw the gun. No matter your skill as a grappler, say, the ability of a gun to dominate you in a fight is incredible. a grappler must physically control your entire body in some manner if just using hands and no weapon. an individual with a gun needs to simply put the opening of the pistol over a part of your body and exert about 6 pounds of pressure with one finger to critically injure or kill you...that is an incredible force multiplier that is difficult to overcome even in prime physical condition.
And keep in mind, the person using the gun doesn't need hours of training every week to maintain their ability to injure or kill you...in fact, reading a lot of these stories, many of these people have little or no training before they successfully use the gun to protect themselves from one, if not more than one, violent attacker.
I would encourage you to read the real life self defense stories at the various gun sites to get a sense of how guns are actually used by normal people every day in violent attacks...it is pretty interesting...