What can I do with this knowledge? As far as I can tell, nothing.
This MIGHT argue against putting much resources into refining your estimate of what is really going on with these aliens. It hardly argues for the validity of the hypothesis.
I think the continuing novelty of the world, the fact that the world continues to unfold in a way consistent with their being just gobs and gobs more you don't know than that you do know, argues for assuming that there is very much knowledge that you, or perhaps your children or your children's children, won't be able to do something with eventually. What of knowledge of aliens among us who may or may not be much more intelligent than us, who may or may not have motives that are hostile to us, that are essentially much more unknown than unknowable? I can think of millions of ways this might be useful, to me as an individual, to my family in contrast to the rest of humans, and so on.
If nothing else, I will be better prepared to act if/when the aliens are exposed or if/when they expose themselves, while my more skeptical friends will be caught flat footed and will wind up in the test kitchens.
Recently I've been struck with a belief in Aliens being present on this Earth. It happened after I watched this documenary (and subsequently several others). My feeling of belief is not particular interesting in itself - I could be lunatic or otherwise psychological dysfunctional. What I'm interested in knowing is to what extend other people, who consider themselves rationalists, feel belief in the existence of aliens on this earth, after watching this documentary. Is anyone willing to try and watch it and then report back?
Another question arising in this matter is how to treat evidence of extraordinary things. Should one require 'extraordinary evidence for extraordinary claims'? I somehow feel that this notion is misguided - it discriminates evidence prior to observation. That is not the right time to start discriminating. At most we should ascribe a prior probability of zero and then do some Bayesian updating to get a posterior. Hmm, if no one has seen a black swan and some bayesian thinking person then sees a black swan a) in the distance or b) up front, what will his a posterior probability of the existence of black swans then be?