Why would it be important to be able to switch cloud providers and keep the same addresses on your internal network? Changing providers while keeping addresses

Why would it be important to be able to switch cloud providers and keep the same addresses on your internal network? Changing providers while keeping addresses seems abstractly like a nice capability to have but it also seems that it might or might not end up being just as much logistical trouble as re-addressing everything when it came down to the implementation...