If anyone watches the Alien franchise, you know that Weyland wants the xenomorph to use as a biological weapon and they couldn't since Ripley and friends prevent that (fortunately). So when I saw the first Alien movies I accepted that premise. It's ok for me.
But now, we are playing a campaign and you tend to play with that original premise and you have to think a bit more about this background or premise. That is, Weyland or other corporations like Lasalle or even another powers like the UPP want the xenomorphs to use them as biological weapon. The players are in the campaign to avoid those plans.
Then, after some sessions, I began to think: how a power could use a xenomorph like a weapon of mass destruction? I try to explain better my question: If you want to eliminate an enemy, it's better and more secure to send nukes to the colony. I supposed that you would want to use xenomorphs, as opposed to nuclear weapons, to not destroy the infraestructure, or to reuse the enemy world in a future... But there is a problem. You have erased the enemy population, but now you have hundreds or even thousands of XX121s living in the world you want to occupy. How would you deal with all of them? I suppose that sending military teams to the world so they could exterminate the aliens won't solve the problem, the teams might die or even a single and hidden drone or facehugger may survive and the infection start again in the new colony. From a corporative and capitalist point of view, using xenomorphs as a weapon of mass destruction is really expensive and the cost-benefice balance isn't suitable. So, I suppose, it's much cheaper and secure to launch a nuke to a world than using xenos.
Have you thought about this? Any answer or proposal? I tell because I am in this situation in my campaign and I don't know how a power can use xenos like Weyland would want to do in the movies.