We use the nutmeg shaker for easier spice adding for good dishes. Give a little to potato puree, and cream soups. Before we grated some from a whole nutmeg, and sometimes forget it, because the grating is a little more trouble.
But the already grated/powdered nutmeg it is only a move with the hand, to shake it onto the puree, and mix it, so easier give that little extra taste to the potato puree f.e.