I wasn't sure the answer to your question so I loaded up the game to check.
As far as I can tell, the CAMP button doesn't do anything except for function as a way to open the menu for the tabs that run across the top of the screen, "Status," "Equip," "Orbment," etc.
Of course, you can also access all of that just as quickly and easily without using the CAMP button.
When I first loaded my game just now, I didn't even have the CAMP button anywhere on my screen, because I had turned it off previously. IMO the game is much better without those unnecessary buttons (CAMP, and also the buttons next to it for the recipes and monster book).
So after checking it, I turned off the CAMP button in my game again. The option to do that is under Options tab, and then change the option of "menu button" to "Off."
Post edited March 21, 2019 by Ancient-Red-Dragon