Dude. Duuuuuude. Would you rather break out a big ol' paper map and GUESS where you are or have a GPS enabled device that tells you EXACTLY where you are, how fast you're going, where you've been, where the spots you caught fish are at and have every map in the US at your disposal in the palm of your hand?
Thought so.
In case you're still confused, get the app. You'll be happy you did. Oh and FYI, the updates are free!