Typical liberal lunacy. Look, if it is economical to do this to ship hulls, it will be done. By "economical" I mean that it will save you more money than it costs to do within a reasonable period of time. It takes a lot of fuel to power a large ocean-going vessel. If operators believe they'll see significant savings from it, you can bet they'll do it. I notice the article doesn't mention how much drag is reduced, which tends to make me think the amount is trivial to the extreme.
It's probably not enough to be worth the trouble as a retrofit, but perhaps it's something that could be designed into new ships. Reduced drag = lower lifetime operational costs, and perhaps even increased speed.
Maybe drag is reduced in sterile saline solution, but the problem with any ocean going vessel is that the hull stays clean at a microscopic level for about a second or two after it's put in the water. After that, algae and plants would fill any microscopic dimples on the ship hull to the point that any improvement in efficiency would be as imaginary as models of global warming. At least that's my prediction, based upon all available data, estimates, models, and hockey sticks I have at my fingertips.