the existence of life outside our world is highly likely, the cosmos is simply too big for earth to be so special that it was the only place where the formation of life occurred. but to go as far as to attach a belief system to it I think is farfetched, much more farfetched is the idea that they can interact with our lives. extraordinary claims require extraordinary evidence. however because it is not believed in mass, and people are not willing to die for it because they have the divine will on their side makes it significantly less harmful than an organized religion.