Distributed armour versus all-or-nothing protection

What is the advantage of a distributed armour scheme over all-or-nothing armour?

It can protect a wider area, whereas all-or-nothing armour gives a smaller citadel much greater protection.

The closing answer compares two ways of preserving a ship's fighting and floating capacity. Distributed armor extends protection across more of the hull and can leave a larger armored volume contributing to buoyancy. The same armor weight must be spread more thinly, so each protected area is easier to penetrate. All-or-nothing accepts a smaller citadel but makes that vital volume much harder to defeat, trading breadth of coverage for greater certainty that the core remains afloat.