Open carry seems to have proven very useful in Dickinson, North Dakota, and some other places where locals showed up to welcome hostile rioters who had been shipped in. Cops coordinated with the gun owners and appreciated what they were doing. These events were the first examples I ever heard of in which the "militia" part of 2A had actually shown its merit.
Here in Florida, open carry is banned. You pretty much have to be at your home or business, and your friends can't give you permission to carry on their property, although some people don't know that. Some Youtube guy carried a rifle while he was fishing, which is actually legal, but the cops hassled him for it.
When the rioters get worse, I wonder what will happen in small Florida cities that get invaded. Without open carry, cops who need civilian backup will be out of luck. People with concealed pistols could show up, but there is no such thing as carrying a concealed rifle legally in Florida.
When you can't display a weapon, the deterrent effect, which is extremely valuable, is gone.