Podcasts are everywhere and are perfect to be used as learning experiences. Not having images turns out to be an advantage in the light of cognitive load theory. The lack of visual distraction frees up working memory to listen, understand and reflect, and leaves room for our own imagination. This causes deeper processing and therefore better retention. Above that, listening is an easy skill that everybody learns at a young age. That makes podcasts an inclusive experience. There are also practical advantages since it is cheap compared to video, and relatively easy to produce and distribute.
Listen to the podcast Why should podcasts be used in learning? by John Helmer, Learning Technologies Expert & Host The Learning Hack podcast: