if you single out one specific function in the Grid Editor vs. using a DAW editor, perhaps not much other than being able to see the drum and articulation names of the notes as your editing them. And the possibility to use the Grid Editor for the Future Hit Instruments like Shaker and Maracas.
Having all the drum-centric tools at hand at the same time is another thing IMO, plus your DAW will not have the Edit Play Style function.
