If we can land on it, then we’ve already boosted to the object’s velocity. Perhaps it would give us a source for raw materials, maybe even rocket fuel.
According to Wiki, some now believe that multiple interstellar objects pass through the Solar System every year. If that’s the case, then we should be able to land on one eventually.
We only have to match its velociity for a short time, iow, a short burn — but would have to be waiting in its path, which means we’d need either a bunch of probes waiting around for such an event, or a better observational system, perhaps in solar orbit out by Neptune.