Don't overgeneralize, though. Yes, using the traditional pipeline is indeed way more efficient when you're creating traditional scenes.
However, this technique of doing everything in a fragment shader can actually make sense for some types of unusual/experimental scenes. Stuff like infinite repetition or fractal detail, smooth liquid-looking geometry with constantly morphing topology, detailed translucent volume rendering. These can be considerably easier to create as a fragment shader.
So, while some people are indeed doing this as an esoteric programming exercise, others also realize that this technique can allow the exploration of different types of realtime generated images.
However, this technique of doing everything in a fragment shader can actually make sense for some types of unusual/experimental scenes. Stuff like infinite repetition or fractal detail, smooth liquid-looking geometry with constantly morphing topology, detailed translucent volume rendering. These can be considerably easier to create as a fragment shader.
So, while some people are indeed doing this as an esoteric programming exercise, others also realize that this technique can allow the exploration of different types of realtime generated images.