It really depends on the podcast as well. There are podcasts which are just free-association rambling (or worse), others which are very closely scripted and ed

It really depends on the podcast as well. There are podcasts which are just free-association rambling (or worse), others which are very closely scripted and edited. I very much prefer the latter, and the best of those approach books in structure and/or value, if they don't directly produce books themselves (e.g., Peter Adamson's History of Philosophy, which is both a podcast and a book series).