There's a great little article over on Podcasting News about whether or not podcasts are a waste of time. The premise is that a person can compute a ton more data in 20 minutes reading than they could listening to a single podcast.
I fully agree with that statement. As a person who has about 50 blogs in his reader at any given time, I know that I can skim through all of them in 20 minutes flat. However, I can only listen to one podcast at a time so in that same 20 minutes all I get is...well...one single podcast.
However, we're not all always about skimming. Sometimes we actually want deeper information or a longer experience.
The sound of someone's voice can tell you if they are young or old, quick-thinking or reflective, appealing or obnoxious, passionate or bored. Podcasts can offer a richer experience of who a speaker is than can easily be conveyed in text.
Podcasting: stop to smell the flowers :)