I'm concerned about the moral implications of creating intelligent beings with the intent of destroying them after they have served our needs [...]

Personally, I would rather be purposefully brought into existence for some limited time than to never exist at all, especially if my short life was enjoyable.

I evaluate the morality of possible AI experiments in a consequentialist way. If choosing to perform AI experiments significantly increases the likelihood of reaching our goals in this world, it is worth considering. The experiences of one sentient AI would be outweighed by the expected future gains in this world. (But nevertheless, we'd rather create an AI that experiences some sort of enjoyment, or at least does not experience pain.) A more important consideration is social side-effects of the decision - does choosing to experiment in this way set a bad precedent that could make us more likely to de-value artificial life in other situations in the future? And will this affect our long-term goals in other ways?