A gun is not a tool you need. It is just needed because you expect others to also have it.
Against random robberies, pepperspray, tasers or sirens are better.
If "the woman at night on the walk home" has a gun, "the robber" has one too. Nothing won.
If it is circulating, you cannot prevent the wrong people from getting them.
I see how not only the police having guns is nice. But this means they shoot way quicker. See the rate of deaths by police in germany, its always below 30.