In these events they talk about the new features as they're the most recognisable for press, often examples of what some of the new APIs are capable. (Features, which could of course have been programmed to run atop 10.7 Lion.)
E.g. growl does system wide notifications, but it's not built-in, and Apple like to control these things so they may more easily interface them with other Apple devices. (E.g. Apple could very easily make their Apple TV notify the user's iPhone when a new TV episode has been downloaded, or even schedule it onto their Mac.)
With that in mind Apple have a history of meshing the experiences across their devices, the messages app is a recent example.
E.g. growl does system wide notifications, but it's not built-in, and Apple like to control these things so they may more easily interface them with other Apple devices. (E.g. Apple could very easily make their Apple TV notify the user's iPhone when a new TV episode has been downloaded, or even schedule it onto their Mac.)
With that in mind Apple have a history of meshing the experiences across their devices, the messages app is a recent example.