It doesn't help us much, since we'll be going against gravity too. ∆v required to reach the object won't change significantly over time, and with present technology, it's the strongest factor which determines what we can or can't do in reasonable time right now.
That's a lot of confidence. This is the first interstellar object passing through imaged. However, we believe several of these objects pass through the solar system per year. Why haven't they been detected until now? We didn't have sensitive telescopes doing whole sky surveys like Pan-STARRS until recently. As more projects like LSST come online, we will undoubtedly discover more interstellar objects. And we will learn a lot more about them from Earth-based observations. Perhaps we will get to the point with telescope sensitivity where we can detect them years away so they intercept is simpler. But I do not share your confidence that we will send our first probe to explore interstellar objects to Oumuamua just because it was the first one discovered.
It may be going fast, but partly that's because it sped up a lot through the inner solar system, as it climbs out of the Sun's gravity well it will slow down a great deal. And the solar system is big. It won't be light-years away in a few decades, of course, it's not going nearly that fast, it'll take nearly two centuries to get 1000 AU from the Sun. So we have all of that time to go out and do a flyby mission. We could put one together today that would reach the asteroid within the next 30-40 years if we really wanted to (at a modest cost of a few billion dollars). If we went wild and spent tens of billions on a mission we could do a rendezvous mission in 20 years. Meanwhile, launch systems are getting better and cheaper so almost certainly we'll get to a point where a realistic 10-20 year cruise timeframe mission is not just feasible but affordable, and then we'll go take a look at it.