The next setting Show top-bar title area? only appears if you have either selected Normal Position or Contain-To-Grid-Sticky for the Main Menu Position setting. The reason why it only appears if you have one of those settings selected is because of the title area of the top-bar menu. I have seen some menu area on sites that look like the following:
The title area takes up the entire top portion of the menu. To me this is unnecessary and looks kind of over board. So when you choose “No, hide title area” this will hide the title area of the top-bar. Notice in the pic above there are two “Home” links. When you select No hide title area, it only shows one Home link and there is no space:
You will also notice that Change text of title area is also hidden in the customizer when No, hide title area is selected. This is because the title area of the top-bar is hidden, so there is no need to for this area to show.