Humanity is the most incredible thing in what we know of the universe. Stars and gas clouds sure are beautiful too, but unless you are very religious, the those are simple an artifact of statistics, there was no intention there.
Without the humans, the universe is empty.
Max Tegmark adds a twist to that statement: without consciousness (subjective experience), the universe is pointless.
Besides, the only alternative is useless optimism - to assume that life elsewhere does exist and implements our values (perhaps better than we do,) and thus we are totally unnecessary and it makes no difference if we all die. (This is the same nihilism inherent in believing in an afterlife.)