It's nothing else. It's primarily, in its current configuration, an air defence destroyer that can track and engage hundreds of airborne targets, aircraft and missiles. Apart from the helicopter(s) it carries, it has no real capability of engaging other naval ships, certainly not those capable of ship to ship warfare. I think the term used is "for but not with", in that it has been designed and constructed to take ship to ship missiles and tomahawk land attack missiles, but those systems were never fitted during construction to lower costs, and it probably will not get those systems until it's due for refit. It can't really protect shipping at this time, it's basically a ship that was built to protect a fleet from airborne attack, yet it's sent there with no other ships to protect.