Other types of plays were successful, but TV and movies could do them better. A romance is more poignant when you see the kiss. But horror, sci-fi, fantasy, things that ask for a collaboration between your imagination and the story itself, those were the types of stories radio really excelled at. It helped that there wasn't much of a need to worry about the special effects budget.
One of my absolute favourite horror series (in any medium) is Wyllis Cooper's Quiet, Please. It's subtle and weird and very much in the tone of The Twilight Zone, which is another of my absolute faves.
The show has an unusual format in that the host, identified in the credits as "The Man Who Spoke to You" and voiced by Orson Welles collaborator Ernest Chappell, just tells you the story. It's a framing device with sound effects and other characters appearing as needed, but it's very bare-bones.
Stripping down the production helps to control the narrative perspective, and that control allowed for more effective twist endings and scares, as I hope you'll notice in this episode.
It's called "The Thing on the Fourble Board" and I'm not going to tell you anything else about it except that it frequently makes it onto Top Five Scariest Radio Episodes Ever lists, and those lists ain't for the faint of heart.
Hope you weren't planning to sleep any time soon!