Living in a "no-firearms" country, I doubt of the usefulness of having open access to guns. I think it creates a placebo effect of security. You feel more secure, but the source of the danger is the gun.
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The gun has more value in being a placebo and for defining social status(like cars or clothes can be used to) than being a really useful tool.
Guns as a placebo certainly exist, and many gun-related accidental tragedies also exist, and gun use as an effective tool also exists in meaningful numbers.
A useful thing to google is the "NRA Armed Citizen column", which comes out in their American Rifleman magazine.
I think at least some of those reports are true, because i personally knew a Russian guy, who moved to the United States and was reported in that column to have successfully stopped an armed robbery of a small store he opened there...
He was seriously wounded and survived, but he fatally wounded one of the robbers...
So upon contemplation and life experience, i have to give credit to the Americans and the US government in most of the States for giving American citizens the optional choice to legally use a gun as a placebo or a real tool.
The vast majority of governments don't give their citizens such a choice. Seems to me that the greatest measurement of "Freedom" is the number of options one has...