Stories provides Instagram users with a chance to share posts at a higher frequency. While Instagram photos are typically reserved for perfectly composed shots, Stories allows you to share the little moments that may not be as picture-perfect.
Instagram is positioning this feature as a solution to over posting. There is a significant separate space where your Instagram Stories live and you can post as frequently as you want without worrying about over flooding your friends’ feeds or filling the grid on your profile page.
Via Gregg Morris