In Super Mario Galaxy 2, if you use the Cosmic Guide to finish a level, you are informed that you will receive a "Bronze Star" instead of a "Power Star". I assumed that meant that it wouldn't increase your total Star count, however, when I finished the level in question (Flip Swap Galaxy's Think Before You Shake level) using the Cosmic Guide (and thereby getting the Bronze Star), my Star count still went up.
Is there a benefit to getting the Power Stars over the Bronze Stars? Or can I essentially get the game to play itself (when available) with no real detriment?