Thought experiment:
Through whatever accident of history underlies these philosophical dilemmas, you are faced with a choice between two, and only two, mutually exclusive options:
* Choose A, and all life and sapience in the solar system (and presumably the universe), save for a sapient paperclipping AI, dies.
* Choose B, and all life and sapience in the solar system, including the paperclipping AI, dies.
Phrased another way: does the existence of any intelligence at all, even a paperclipper, have even the smallest amount of utility above no intelligence at all?
If anyone responds positively, subsequent questions would be which would be preferred, a paperclipper or a single bacteria; a paperclipper or a self-sustaining population of trilobites and their supporting ecology; a paperclipper or a self-sustaining population of australopithecines; and so forth, until the equivalent value is determined.
If we ignore the possibility of future life arising again after human extinction, paperclipper seems (maybe, a bit) better than extinction because of the possibility of acausal trade between the paperclipper and human values (see this comment and preceding discussion).
The value of possible future life arising by chance is probably discounted by fragility of value (alien values might be not much better than paperclipper's), the risk of it not arising at all or getting squashed by its own existential risks (Fermi paradox), the risk of it also losing its values (e.g. to an UFAI), the astronomical waste of not optimizing the universe in the meantime, and possibly time discounting of the (very distant) future.
(All of this discounting might still be smaller than what takes acausal trade to work out, so it's not clear which choice is better. A cleaner question would compare a paperclipper with a sterile universe.)
Some people reasonably think that value is simple and robust. Alien life will likely tend to share many of the more universal of our values, for example the "epistemic" values underlying development of science. ETA: Wow downvotes, gotta love them :-)