Valid points, but I can't imagine that these won't be addressed in version 1.0. Google points out in the about page that
Google Desktop Search is still under development as a beta product. We intend to add new file, email, and chat formats and browsers as Google Desktop Search evolves, and when new formats are created and used. If there's a format you'd like Google Desktop Search to be able to search, please let us know. We can't guarantee that we'll add every type that's suggested, but your suggestions will let us know what formats are important to you.
It sounds really good and everything, but it solves a problem I don't have. I have a neat and orderly "My Documents" folder, a well organised set of email folders, and I bookmark useful web pages and categorise the bookmarks. It may be useful for searching source code, but I don't need to that often.
I am impressed that Google have developed so many variations of a search engine. I often use the calculator for conversions, for example. I'm looking forward to whatever they release next.