It is still unclear what Wave’s tangible benefits are in general. I think this is largely due to it being an evolving platform but this option of creating an embedded and public wave could make it useful for live blogging in particular with the added benefit that participants could help flesh out the blogger’s notes with more detail, making it a richer resource for others.
You can also embed a live stream with FriendFeed and I’ve done that in the past quite easily. This Wave option is potentially more versatile but it may depend on who is interested in using it. That being said, the option to expose the wave to the public and to even permit anonymous contributions could make Wave that much more appealing in general.