The debate between aliens and demons is impossible to win…until we have some total disclosure of all the classified intel and the secret libraries at the Vatican are opened.
To me it makes no difference, though. It's just semantics at this point. Because I know that there is good and evil whose reach extends beyond the visible and physical, no matter what we call them.
I think it's worth nothing that through the ages these other-worldy powers were always called angels and demons or spirits. The ancients never thought of them as "aliens." I think we have too readily dismissed the wisdom of the ancients, thinking we knew better. At our peril.
The only point where the distinction between ETs and spirits might be relevant to me is if we're talking about other phsyical, corporeal, conscious beings on other planets who are equally bound by the same earthly laws that we all are, asking the same questions about ETs versus spirits. I've started leaning away from this possibility, however, even though I believed in ETs for quite a while. I'm starting to wonder if we are the only corporeal "conscious" beings in the universe. So in that sense we are "unique"… but we are not alone, because there are so many non-corporeal conscious beings who know about our plight.
Some of us might find out the answer to these questions soon enough.