You will never learn how to cook by listening to it. You will never learn to ski by listening to instructions about it. You will never learn 3d graphics programming by listening to podcast courses.
You will learn a lot about Roman history by listening to it. You will learn a lot about the Spanish language by listening to it.
If you avoid learning things that you can't learn by listening, then you will only ever learn things that can be learned by listening and that will bias your perspective about learning anything.
That's not the point I'm making. The point is that people do have "learning preferences" and these have an ultimate effect on learning.
To use your example: some people prefer listening to Roman history podcasts. Others would rather watch a film. Still others prefer a book. If you want to maximize learning, it seems best to pick the style/format most suited to your preferences.
You will learn a lot about Roman history by listening to it. You will learn a lot about the Spanish language by listening to it.
If you avoid learning things that you can't learn by listening, then you will only ever learn things that can be learned by listening and that will bias your perspective about learning anything.