On the whole, it allows Google greater freedom and secrecy, the can recruit money from venture capitalists, and capitalize when their projects gain. Really, it's a very strange way for a charity to set up. Obviously making money isn't the most important thing, but you can tell that they certainly wouldn't mind.
The Google.org retrofit kit aims to reduce global warming by providing an inexpensive way to convert your average 20-30 mpg gasoline car to a 100+ mpg gasoline / ethanol / electric hybrid. This isn't something I really expected from Google, but they have my permission.