The bitrates I've found so far are roughly 40 kbps for cable-based transmission and ~300bps for air transmissions. It should be possible to get even better speeds with more tuning of quiet's profiles. In empirical testing, I've found the air transmissions have a range of a few meters, but it really depends on how the speaker is oriented with respect to the microphone.
As for the advantages, of course traditional radio-based transmissions have many advantages. Quiet has a few though -- for example, with its javascript bindings, you can use quiet to share data between native apps and the browser. You might do this to share what's in your clipboard, share contact info with someone, pair devices etc. Additionally, you can get quiet up and running very quickly, without the need to join any networks.
As for the advantages, of course traditional radio-based transmissions have many advantages. Quiet has a few though -- for example, with its javascript bindings, you can use quiet to share data between native apps and the browser. You might do this to share what's in your clipboard, share contact info with someone, pair devices etc. Additionally, you can get quiet up and running very quickly, without the need to join any networks.