After playing with WAVE for a few months I was a bit under-whlemed, too, by BUZZ.
But, it appears to be in its infant stage and provides all the 'services' of Twitter/Facebook/etc (albeit those services are arguably useless) in one convenient place.
I am reminded of the 80s when, in corporate IT, you heard "No one ever got fired for choosing IBM". Google seems to be the one to follow. It is remarkable that Google can provide a service (without any hype) and steal attention from the other, more established, services in a few days. Even Microsoft in its hay-day couldn't do that!
I am on-the-fence about BUZZ. And I am disappointed that all my efforts to learn how to write apps for WAVE may be wasted if BUZZ does not provide the same capability. But having everything in my GMail account - which provides THE BEST spam prevention, bar none - is quite convenient.
The trend to push everything into 'the cloud' is one I favor. A single, very light, interface to all my data makes my computing truly portable.