A short story's biggest potential, to me, is the advantage on leaving an open-ended conclusion.
I'm pointing not to the genres but more to the structure as a whole. A short story's AMAZING in conveying certain concepts that don't have potential to be stretched out into a series but just enough to get people thinking. Say rhetorical questions, or actions of man in certain situations. It almost works on any genres, from the most harrowing of horrors to the most laid-back of Slaisu-offu-Laifus.
Grab some random thoughts you'd have before you go to bed, like: What if a rat was hired as a caretaker for an elderly cobra? Or: What would daily life be like in a deserted world where only you and living essentials exist? Or: If cows took the place of humans, would they slaughter us for skin as we did with them? Or: What if the aliens are already here?
You know, strange shower thoughts and stuff.