Eccentricity describes the shape of an orbit. 0 is perfectly circular. Between 0 and 1 is elliptical. 1 is parabolic. Above 1 is hyperbolic. So an eccentricity

Eccentricity describes the shape of an orbit. 0 is perfectly circular. Between 0 and 1 is elliptical. 1 is parabolic. Above 1 is hyperbolic. So an eccentricity of 3.0 is hyperbolic, which means the object is of interstellar origin. (Picture the shape of a hyperbola in your mind. An object on that trajectory can't come back to the same point.) With the uncertainties that come from fitting early observations, these numbers can change as more observations come in. At 1.07, it would still be possible that the final orbit turns out to not be hyperbolic. At 3.0, that's much less likely. What makes this discovery exciting is that it would be the second object of interstellar origin that we've discovered in our own solar system (and both discoveries are fairly recent). That's a new class of object to be studied and presents an opportunity to learn something new. The fact that these two discoveries are temporally close suggests that we'll discover many more as our technology and technique improve.