Yes, independent or no, governed by a cabal of financiers or a collection of fools, its function has grown way beyond simply raising money for the government or clearing debts between banks.

BBC: Central banks are part of the state

That kind of military intelligence collection and analysis is an essential national security function.

CENTERFORSECURITYPOLICY: Center for Security Policy | What hazards along the road to Damascus? Mission impossible

Solar panels, geothermal energy and rainwater collection will ensure that the massive manse can function through any natural calamity.

FORBES: Off-The-Grid Mansions