I think podcasts, audiobooks, and books are all information, and in general there are a huge number of purposes and formats and its a bit silly to treat any type of presentation as being specific to a particular purpose. Not everyone has the luxury to access information in their preferred format either.

For me what is often challenging is how much variation can go into the audio that can challenge my purpose, a dry or mechanical recitation of the text vs a skilled telling vs a full cast that is comprised of a huge variety of performers.