It is also quite surprising what can also happen "off plan". Our destroyers at the time had quite a lot of magnesium (so I was told by someone who probably knows) in their superstructure (nice and light).
This happened: https://en.wikipedia.org/wiki/HMS_Sheffield_(D80)
One of the Exocets (https://en.wikipedia.org/wiki/Exocet) deployed by a Super Etendard hit, went in through the side but failed to detonate. Instead, the heat of its still burning rocket set the ship on fire.
Extinguishing a fire involving metals like Mg is quite tricky on land, let alone at sea. The damn stuff tends to carry on burning regardless of what you throw at it. On a ship it's much worse because the whole point of a ship is that ideally the water stays on the outside.
There were several other compromise design decisions. For example, whilst chatting back to base in the UK via satellite, quite a lot of radar had to be switched off to avoid interference. That means that you don't even know that a pair, flight or even a sodding wing of Super Etendards are heading in your direction, equipped with missiles that are deployed BVR. They siddle up to you after a refreshing stroll around the wave crests and a couple of tube rolls and then punching a hole in you and burn you to the waterline or explode and make a real mess of you.
The explanation given in WP is probably better than mine but then I knew someone who was there. Who knows? I note some discussion on the talk page about Al but I distinctly remember Mg being mentioned by my source. I may be wrong about that - it was a long time ago.