I will carry what I need to survive, in a minimalist conception of that term, on my body (in my pockets and belt. I will carry in the vest what I need to do the work I am doing (navigation, water, binos, camera, communications, etc) so I have easy access without dropping a pack and digging into it. It also stays with you when you do drop you pack. In the pack is everything else. Think of it as layers, I can survive without the pack and vest, but each layer enhances my capabilities (and comfort).

I have never been worried about style or opinions when I am out. I have almost always been responsible for the safety and security of others when I am out, so I carry what I need. I think most people make such decisions based on comfort and effort (or reducing effort). A vest can be a little hotter.