This is going to be pure speculation, but I wouldn't be surprised if this was an acquihire based on the work Pixelapse did on reading different file formats and versioning them.
Pixelapse wasn't a fully formed product, but I'd bet that what you see integrated into Dropbox is the ability to read these formats well, and that's pretty much it. I think it's unlikely they'd create a dedicated Dropbox feature set that caters to designers and creatives.
I was kinda excited at this acquisition, but what you said makes a lot of sense. Crap.
LayerVault is an awesome product, but nothing good comes out of a market with a single company in it :(
I have never heard about Pixelapse. Is it something like Layervault? (I have used neither) Because it seems like it is, with "version control for designers", and content like "Every single version of your design is saved on Pixelapse." "Every version of every file is saved for eternity." on their respective websites.