Facebook is always rolling out new features. It's a way to stay relevant and keep up with the competition like Snapchat and Instagram.  The stories feature lets you capture moments of your day to share and it only stays up for 24 hours.  But it could also be a way to find out who's looking at your Facebook page.
I posted a story on Facebook early Monday morning.  When I looked this morning, I could tell 180 people watched the story.  If you click on the eyeball in the bottom left corner, you can even see the names of the people that watched. Some of the people I know very well, others are acquaintances and some... I don't know at all.  These names are a good indication who looks at my Facebook page regularly, and it could show you who looks at your page.
Keep in mind all of your Facebook friends can see your story. So, maybe you don't want grandma or people you don't know seeing you partying with friends.  If that's the case, then you can send the images or video directly to certain people simply by taking a photo or video, then clicking only on the friends you want to send it to.  That can give you a little more privacy. 
It's very similar to Snapchat and Instagram.  Facebook Stories is currently only available on your phone.  You may not see it if you haven't updated your app.  Once you do, you'll see the airplane at the top and circled friends.  Just remember, if you click on their story... they'll know you watched it!