Having lots of copies of the same thing in different places, and trying to manage them, is one of the reasons we made layers and added the ability to have more than one visible at a time.
We certainly could add a Copy to Layer option, and we will consider it, but the way we intended this sort of thing to work is to create a layer for things you want to see regardless of what voyage plan you’re working on. In this case, you might have a layer called “Navigation Hazards” where you move all of your hazard marks. Then you can leave that layer visible all the time, or turn it on and off as needed.