A few years ago I took one such ferry from Palermo in Sicily to Naples. It had a small, but adequate cabin and public areas to visit when not in the cabin. Being an overnight trip, no serious sightseeing or business time was lost. Very convenient.
I recently was on a cruise that covered, among other things, the Tyrrhenian Sea part of the Mediterranean (it's bounded by Italy, Sicily, Sardinia and Corsica).
From the cruise ship in several ports I saw that ferries of the Tirrenia line are being repainted using supergraphic images of American superhero comic book and movie cartoon figures.
Take a look:
Other ferries carry images of Batman and Wonder Woman.