The point of having multiple boards is to have a separate inventory of things outside of your normal household groceries list.
A Camping Board
You could have a separate inventory of items and recipes for an upcoming camping trip. You can also add things that are not necessarily things you need to purchase from the store, but instead add items to the shopping list that you need to pack and check them off as you pack them. This has made our family camping trips much more efficient and so we tend to go more often and more last minute.
A Special Event Board (like a wedding or catering an event)
If you are catering an event and are feeding a bunch of people, you can have a separate board so that these items don’t become part of you normal daily shopping list.