Posting through blog to be read more broadly requires other promotional media such as posting on the forums or submitting the link in blogsphere (blogger community network). Social media is a powerful medium to reach readers and also anonymous online readers that able to follow latest news from blogs which is come from keyword searches on google.
Making page on Facebook is purposed to promoting the latest posts of our own writing, it can also reach anonymous visitors who want to follow the latest posts via their home page by clicking "like" before. Besides having a Facebook page is helping blog owners to interact with non-bloggers about other things, like telling the latest status, holding events / contests, or even be able to selling our products and services.
There is no absolute requirement on making page for any bloggers, your blog don't have to be popular by having hundreds of visitors per day and also has a diverse and unique contents, It's recommended for beginner bloggers to create an official page on Facebook and then build a network with readers.
Of course, to manage a page on Facebook, the post links should be routine to broadcast for linking latest posts or old interesting posts so that can attract discussions on a regular basis with no intention of spamming. In a recent post a link, add an outline of the topics to entice the reader to click on a link that appears on their home page.
One note, when our readers clicked "like" button, make sure they are not bots derived from web services ("like" is easily manipulated) at least the biggest benefits of having a blog page is blog owners can interact and get feedback from readers. We liked it better than when you post something, they simply click the "like" and then disappeared, which is more severe there that promote their pages (spam).