"isn't vegas primarily a video app?"
Its funny you should say this. At their forums, the vegas histroy is being reviewed for the video guys. SF's marketing has been so piss poor on the audio side that this is what people think.
In truth, first they had sound forge, a two track editor, which is now in version 7, and pretty nice. Then they put out acid a looping tool. Vegas Pro came out soon after. It had a video playback feature just like sound forge did. The audio editing system vegas uses was so intuitive for some people that the video features started piling up, and video was treated the same way as audio. After a while there were two versions, Vegas Video, and Vegas Audio, which were identical, save that Vegas Video had more video tracks. Now they have dropped the name back to Vegas