>>719831042 (OP)
kind of a gimmick, the DS screens generally just acted as either single vertical screen or had secondary info on the bottom screen to clear up UI on the top.
in a way its a better implementation of what bandai were doing with the wonderswan where it have either a vertical or horizontal screen depending on the game.
i liked what monster hunter did by having the touch screen be a customizable set of buttons for various actions and info like items, crafting, keyboard and the like