Nemi ships versus Ptolemaic giant galleys

Could a ship like Caligula's Nemi vessels have been built for war?

The Nemi ships were pleasure vessels. The Ptolemaic forty was armed, though its size suited display and artillery better than agile ramming.

Caligula's Nemi ships were floating pleasure palaces. The Ptolemaic forty was an armed giant galley, although its hull arrangement remains a reconstruction. Its launch required a large trench or dry-dock arrangement. Reported crews included 4,000 rowers and nearly 3,000 soldiers, with other personnel potentially taking the total towards 8,000. Despite its rams, its size made agile attacks difficult. Its size suggests a status vessel and mobile artillery platform.