Well… for me, just moving the character with your keyboard is sufficient.
But I think it’s a question of what platform you wish to play afterwards…
So if you wish to convert your game into a nintendo ds/3ds/2ds game for example, the keyboard would be a better choice I guess, but for PC games and so on, I suppose the mouse option would be better…(thats only an example!)
But if you ask me, you can drop the mouse support, as you can also play with the keyboard in PC games…!