It means that googles launcher now has the same status as any other third party launcher. It isn't a built in system component, but just another piece that can

It means that googles launcher now has the same status as any other third party launcher. It isn't a built in system component, but just another piece that can be swapped out (or in) at will by the end user. Remember that for the majority of android phones sold, Samsung is the company dictating what software is installed by default. This is a play to get users to replace Samsung's launcher with Google's launcher. They want nothing more than for you to use a third party launcher: theirs.