Okay, how useful is it to be able to create a Project Workspace but NOT be able to view a .mpp file in the browser? There are third party services out there that allow you to view a MS Project in the browser, so why not Office Live? I'm not even alluding to the ability to edit the document (though that capability should be offered at some level of the service).
If all I need to do is share a .mpp document, I can do that in any workspace. I don't need a special "Project" workspace.