That's the point. It makes things easy to use.
It supports all the hardware that is possible for Linux to support at this time. It supports all the configurations that is needed for desktop audio. You don't have to go out and ditch your hardware that works perfectly well in any other OS. You don't have to memorize the specific alsamixer settings for your stuff to work. You don't need arcane knowledge of drivers and configuration utilities with different documentation or anything like that. No editing of text files.
It does what is needed to be done.