I don't know, what does learning any fact about the universe that is not directly applicable to my life do for me? Aside from potential side-effects (it's not uncommon that knowledge-seeking about one thing yields seemingly unrelated applications)... if you have never experienced the joy and satisfaction from learning and understanding something new, I can tell you, you're missing out.

So, while not knowing and learning about civilizations beyond Earth certainly does not negatively affect my life very much, I still assert that life would suddenly get much more interesting if we did. There is a reason why Alien Sci-Fi is very, very popular...