Only it's good when you don't have merchants in the area. But if you do have lots of them in the area, in this case, China really does, then it is a huge pain in the ass. Maybe you do get to practice live rounds on those pirates like the colonialists did on bushmen, but does it worth it if you lose a few big cargo ships? The hijacked Saudi supertanker MV Sirius Star, itself worth $150 million and another $100 million of crude under full load (probably close to 150mil at current price). If it was a container ship carrying high tech merchandise from Asia, it could easily worth few hundred million to more than a billion. Then what do you do? If the pirates go mad and sink the ship (actually pretty easy, just open up those water-gates? doors? in the bottom of the hull), then what do you do?