#1: Keep Your Ideas Somewhere
A blog doesn't have to be about blogging and it surely doesn't have to be your everyday "share-with-the-world" blog. Blogs can be private. Blogs can be a rich place for you to store your ideas for writing projects, query letters, and free writes. A blog allows you to try new things without the repercussion of NEVER writing it at all or trying to publish it before it's ready.
Of course, you can blog publicly, but don't feel obligated. If you blog publicly, you may want to develop a niche blog about something you are really passionate about. Do you love to garden? Do you write stories about huskies? Do it and never look back!
#2 Generate Book Material
The idea of blogging a book isn't new, but maybe you haven't considered it. You can use a blogging platform like Medium, Weebly, or WordPress to write your next book. Think about it? You could pen your rough draft, day by day, with a blogging platform and share it with fans. By doing this, you are accomplishing several pivotal things in the publishing world: garnering buzz for your book when it is published (self-pub'd or via an imprint) because you are intimately engaging with fans, and working through the hardest part of any book, the first draft.
#3 Slowly Earn Passive Income
You never have to make income by blogging, but you post a few ads here and there to help cover the cost of your hosting fees. Heck, you might be able to generate a solid side stream of income if you are blogging a book about a topic people are actually interested in...