Getting back to the topic....
I'll never be able to prove it, but IMO the big reason was to show the average Joe and non-military-savvy politicos around the world that we were serious this time. I know BB's can't control the seas like they once did but to most people they still carry a formidable intimidation factor. Naval experts would, and did, laugh but they weren't what I consider the intended audience.
They would still carry a healthy propaganda punch in much of the world but their manpower costs are far too high.
The argument on that has been fought back and forth on THR. Modernizing the electrical, propulsion and weapons would shave hundreds off the manpower requirements. The savings in billeting space could fit more AA, AS and cruise missiles than any platform afloat today. The Marines had a plan to pull the rear turret and put in a flight deck and hanger space for helos and Harriers. You could fit a hell of an assault force on that ship.
Self-defense weaponry, naval gunfire support, Tomahawks and a company or two of Marines for air assault.
Assuming the thing could be refitted for a reasonble cost and the hull was not too degraded by time.
Which was what the arguments hinged on, cost and remaining useful life of the hull.
