At the minimum it's a question with some intellectual interest, because the idea that the government might need the power to designate certain people as being outside normal criminal or military law first arose with the law of piracy. Pirates were stateless actors, committing their crimes in areas with unclear jurisdiction.
But one problem with taking this framework and applying it to terrorism was the claimed need to interrogate terrorism detainees. There can't be much of a need to interrogate pirates. After all, if you have them in custody, you probably have their entire ship. The crew is the cell. The plan was to do pirate stuff. There's no thread to be pulled on a vast conspiracy. Terrorism may not be like that -- or at least that's what the Pentagon said. But then the interrogations, conducted without the rights of a criminal suspect or POW, make an actual prosecution more difficult. Hence the Guantanamo Bay shambles that Barack Obama will have to sort out.
This may be one reason why the Pentagon rarely mentions the legal options for dealing with piracy, instead emphasizing the security aspects. Because resurrecting the old piracy laws (which must still be on the books?) might remind people of how the framework got corrupted through application to the war on terror. It's the kind of thing that Edmund Burke might have warned about.
UPDATE 5 DECEMBER: In the New York Times, Douglas Burgess says that pirates are terrorists but not quite enemy combatants, and recommends a combination of universal jurisdiction and the International Criminal Court (or something like it) to deal with them. Of course one problem is that Bush administration has been opposed to both vehicles -- perhaps thinking about their personal legal peril from the War on Terror.