Well, among the living areas which are placed in yachts; single cabins are not at the first raw, to be honest.
By saying "living area" I eliminate the engine room and the wheelhouse; one of which is the heart and the latter is the brain.
So amongst the other areas left in a yacht; the main living area is generally considered to be the deck, the exterior areas. This is valid for the yachts that are used during the summer time, of course.
The second important overall; and the first one on the interior is generally accepted as the main saloon. Then comes the master suite; and after that if there is no vip cabin; comes the single cabin...
However, if you are not a yacht owner; the cabin you will sleep in would most probably will the single one.
Since they are also designed in a way that enables them to be converted into a double cabin; they are considered as quite functional areas.
Well, let's see same examples: