Why we have to make blog posts

I am trying to think about why I am writing these blog posts.  I do not feel like I am doing anything other than wasting time that I could spend researching my topic for my issues paper.  Is blogging a skill that you need to survive in the professional world?  Absolutely not.  I am not learning how to write any better.  Perhaps the reason that we are required to keep a blog is to improve our gross words per minute when we type.  I definitely feel like my fingers are flying with elegant grace over my keyboard.  Is a blog anything more than an online journal that anyone can read?  I know that my blog posts are not very insightful.  So what is the purpose of writing blog posts?  Perhaps one reason that we are required to write blog posts is that it keeps us writing constantly.  If we are in the habit of writing and committing our thoughts to paper, or a Microsoft Word document, then it will be easier for us to write our essays.  Or even maybe it is so that we can spend more time out of the classroom thinking about writing.  I do not really know why we have to post on a blog.