If you look at the boats that ACTUALLY TRAVEL THE WORLD, as opposed to
those found in crowded Carribean anchorages, you will find a
substantial portion of them are metal, usually steel, but frequently
aluminum.

no, you will not find "substantial portion" to be metal. The vast, vast, vast
majority of them are fiberglass. You will find a higher % of them to be metal
than compared to the general boat population, but by no means a "substantial
portion".

The real advantage of a metal boat is that it is cheeeep on the used market.