Indeed. I know someone who owns a gun and lives in a very sketchy area. The previous tenant in the apartment was a drug dealer, so sketchy people keep knocking on the door.

Making it very clear that he owns a gun effectively drives all of them away.

But that's where you make clear you have a gun. Concealed carry, by definition, is hiding that fact. There are pros and cons to open carry, but IMO, if you want the gun to act as a deterrent, open carry probably is a lot more effective than concealed carry.