The more we can learn about other planets, the better we can understand our own. Think about how exciting it is that a satellite (Juno) is helping us study Jupiter. The information we can retrieve about Jupiter will help us study how it was created in our solar system. Furthermore, how our own planet was created and ultimately, how our solar system was created.
I think we always crave that knowledge of our origins. Why else is the time before the Big Bang such a sought-after mystery? I can't even begin to fathom an explanation for a time that even our "Laws of Nature" do not dictate.