Over two and a half thousand years ago Sun Tzu told us that all war is based in deception. It follows that the less your enemy knows about you the less likely he is to be successful in his attack on you. So if you want to increase your chances of surviving a criminal assault, keep your weapon hidden until you're ready to use it.
There are times when there is good reason for open carry, but even in those times, I'll still be carrying a hidden pistol. And in those times, I'll keep my unconcealed weapon hidden by keeping myself hidden, to whatever extent it's practical to do so.
There are many ways this advice can be manifested. For example, is it better to stand on your porch in plain view holding the famous Joe Biden double barrel shotgun, where you are an easy target for a hidden sniper, or remain inside where they can't see you? Either way you can find a way to communicate your message; it's just a matter of how smart you want them to see you as being, and how much you want to survive.
Likewise, if you have to approach a group of people you don't know that might be hostile, is it better for your entire group to walk up to them, or for some of the group to stay hidden and watch what happens through rifle scopes?
Open carry certainly has its advantages, but it also has its disadvantages. There is a reason vests designed for concealed carry are often called shoot me first vests.