The reason they're so famous is because it is in the form of a conversation (generally). I like to take in information if it is in the form of a dialogue rather than simple one sided text / monologue.

Podcasts aren't meant for you to get upto speed on some high end technical concept. It's a lay person's perspective in most cases. So I'm fine if Joe Rogan interviews a scientist since unlike a lecture from susskind, I don't need to pay full attention and take notes. Similarly with finance podcasts, where I'm a professional, I don't need to find one which discusses a full economics paper. I prefer one where highly technical people get together and have a high level conversation since I know the basics and I can follow their train of thought.