This switches your normal G3 connection to a G2 connection. Why? Saves alot of battery power, if your only on 50% batt and want that to last you for the rest of the day/next day this is one shortcut tool to use.
Its not much of a sophisticated app (because its simply a short-cut) but when its on one of your screens you'll be more inclined to use the feature to save battery when needed.
(cant find icon pic sorry)