I hope this opens the door to E.E. "Doc" Smith-style "intertialess" drives. There would still be the weirdness of time dilation, but it would be possible for people to travel to distant stars and back again.
Just being able to have matter that has gravitational attraction and little or no inertia or vice versa doesn't open the door to inertialess drives. To do that, you'd need negative inertia to cancel out the inertia of payload and bits of spacecraft that have inertia. And I don't see anything in the article to suggest that there was any hope of that. In fact, I'm not sure how this would be useful unless you could turn gravitational attraction on and off. If you could do that, perhaps you could rob the mass energy of the one or both of the bodies to create energy? It would basically function as a mass energy converter. But we're a long way even from a theoretical framework for that.
One step at a time! Before this, I thought we weren't sure those two were even separable.