Guns can be used only to save yourself from danger. And I think it is fair use.
What seems to be the case in the USA is that when the bad guys think there are probably some guns in and around an area, they avoid it. It doesn't matter if it's one gun or a hundred.
For example, they don't attack the local AR15 club meeting or the Glock two day training sessions.
They attack the defenseless old lady at the bus stop, or the school cafeteria (gun free zone).
Hence, instilling that fear into the bad guy is what is important, more so than having a weapon for your own protection or that of those you love.
What is sought is the creation of a cultural milieu in which the bad guy is scared to make bad acts.
They are basically cowards....
I would not say that engaging in almost any form of crime is 'cowardly.' There are a variety of risks, but having one's face peeled off by a shotgun blast is certainly one of the more emotionally potent.
Much crime is driven by desperation and some by run-of-the-mill stupidity and lack of self control. These classes are the ones who end up losing most often and are certainly the ones who pose the bigger risk to the innocent victim. Criminals also victimize one another probably at least as often as they do the innocent. When the FBI studied the problem of 'guns', they realized that for most criminals, not possessing a gun was a non-option largely because of this. Thus, the strategy of making use of a gun in the commission of a crime carry extra-high penalties. This was remarkably effective which is why real gun problems (as opposed to phony staged 'active shooter' events) have been declining significantly over the last four decades and are now at very tolerable levels.
I'd say generally that criminal are business people in a particular business and make rational cost/benefit analyses just like any other people in any other business. As a gun owner I do my best to make sure that criminals are cognizant of the risk side of the equation.
Gun control with crime involved is pointing to a breakdown of society. People who are desperate will gradually move to the countryside. There are lots of lands around America that are only owned by government. People will form their own small governments as they join together with their guns to battle off forest rangers, kinda like the Bundy incident, but with folks living on the land that they take over because it is the only logical desperate measure.
With communications as they are, the face of America will change as these groups strive to help each other.