There is something special here, which is the unique combination of biospheres and natural processes that enable life as we know it. Maybe aliens also have the same life form as us, and they are looking for similar habitats? Our search for such habitats so far has not been very successful, which shows that we are a indeed one of a kind in the known universe.

The aliens who can visit us, however, are likely to possess technologies to terraform unsuitable planets. But maybe their technological development was not well rounded and space exploration was pursued way more than other form of technologies. Remember that we went to moon before we had smartphones. Just a simple analogy, but who knows?