According to Facebook:
“Promoted posts are an easy way to get more people to see your posts. Promoted posts appear higher in News Feed, so there's a better chance your audience will see them. There are two ways to promote a post: from your personal account and from your Facebook Page.”
One of the most amazing features of promoted posts is that it also allows Geo-Targeting:
We will cover best practices with the benefits and disadvantages of promoted posts in upcoming sections.