You know, no matter how you twist and turn that explanation, there's just no way it holds water:

- If you take away the SD card, you STILL have to decide a place to store your music. There's STILL a file system to place it in.

- If you DON'T take away the SD card, you don't have to use it. You do NOT have to consider if the files are stored there or elsewhere.

- There is no direct correlation between the number of physical storage locations and numbers of directories/places to store data. Especially in a Linux file system. You can have as many or few file directories as you want, except for the default system folders, that are indeed already many enough to confuse anyone if they'd not make some pretend point of the one extra /sdcard folder.

So the point hardly even makes sense even from a marketing point of view. It only makes Android look unorganized as a whole.