So there are several wave-integrations for wordpress. I'm gonna try to make a more specific one and also explain the bigger picture.
First, of course we shouldn't integrate with the google wave API, WordPress is an opensource, decentraliczed platform, and should remain so, however google has promised to release the entire wave platform entirely opensource, some parts of the code is already open sourced, with more to come.
For what should the wave integration protocoll be used then? Well I'm a blogger myself (I suppose many of you are as well) one of the reasons I keep on blogging is that I get feedback from my readers through the comments, however, I rarely get a discussion going, because people tend to drop a comment and then not check back for my respons. Enters the wave protocol! This is exactly the kind of situations it's designed for.
If we make it possible to use wave for comments, all blogs using it will merge together into one wonderful, decentralized discussion-forum, pushing the blogosphere to the next level!