I totally agree, Mark. With attention spans ever decreasing, short fiction is a good format for Medium. I have also learned that short humor works equally well as short fiction. Obviously, neither is preferred by Medium, but that is another story.
Sure, there is not much money in it. But what do people expect for a 50-word story or 7-word poem? Do it for the love/fun/challenge of it and enjoy some extra pocket change. They could lead to new followers and reads of your longer stories.
I enjoy the challenge of microfiction. It is difficult to write something interesting in so few words. It can sharpen your writing.
One of my most popular stories on Medium is a 50-word microfiction story that was funny. It even got curated under both Fiction and Humor.