Comment by the_af

You have a point. Maybe if I hadn't read the story first it would work better for me.

In the story, there's little doubt these are aliens (though their physical form, if they have any, is never described). If there's any doubt, it's about what they are talking about -- but this is dispelled pretty soon too.

I think the real reason is simply budget.

I can understand the limitations of working around budget, and constraints sometimes spark some inventive storytelling, like in the pretty cool "The Booth at the End", which has a very similar minimalistic setting in a diner! In fact, this short somewhat reminded me of that much better show.

(If you haven't watched "The Booth at the End", I strongly encourage you to do so... it used to be free online ages ago, not sure now).