I'm scratching my head here. It seems that the buttons on the Post page of 2.5 and 2.6 "Add Video, Add Audio, Add Media" are all useless.
You've just got the wrong idea about what they're supposed to do.
If you want to embed audio and video on a web page, you need some sort of third party tool to do that. WordPress does not include one.
The Add Video and Add Audio sections are pluggable. They're there for plugins to add functionality to. The Image stuff is included, because it's pretty easy. The audio and video stuff needs flash players or something similar if you want to embed things, and everybody wants that to be done in different ways. So WordPress doesn't attempt to do it, you need to get a plugin for it.
I'm really confused. Why should these buttons be revealed to users if they don't do anything? It is trivial to hide the buttons unless there is something behind them.
Suggestion to WordPress Developers: don't reveal buttons in the user interface that aren't pushable.