Got a note from the Mystery Writers of America, a group to which I belong, indicating that they have done some revision in regard to allowing people who write for epub to become members. That wasn't on the radar when I joined, and not even a couple years ago.
Pro organizations have always required publication by well-known presses to qualify a writer for membership, and some small presses made the cut, but not vanity presses.
Self-published stuff still doesn't qualify you to join as a working pro, but the criteria for small epublishers are going to be such than it won't take all that much to qualify.
And the beat goes on ...