In order to answer this question, you need to answer another: Why are you writing?
If you are writing because you want to build a writing career through self-publishing where you are planning on marketing your own books and constantly developing new books and promoting them, you should edit the book as best you can afford and self-publish it on Amazon.
If you are writing because you enjoy it, or somebody told you that you should write a book about your life and you don't care if you have to give it away for free, you just want it to be available to other people, you should blog your writing.
Here is the problem- when authors who want to make their living from their writing are at a disadvantage because of those who just want to write. These authors will still probably need to give away their books for free in limited supply, but instead of reaching a target audience, they will reach many people who are addicted to collecting free books. These people will never pay a penny for another book no matter how good it is because there are so many free ones. Yes, I have actually met these people in real life. Publishing a book just to give it away free indefinitely is counterproductive. For one, a lot of time, effort, and money go into publishing a book - even if you do if for free on Kindle or CreateSpace. Maintaining a blog does not require as much work.
Some people are interested in making money off their writing, but instead put in on a free blog. If you post your material on a blog, you will not be able to sell it. If people are getting it for free, they will not then pay for it. (Unless you only post part of it, such as a first chapter that grabs their attention.)
Blogs are a great place to start writing, though. The most frequently posted Guru jobs are along the lines of "finish my book." If you are not in the habit of writing, a blog will make you or break you. Blogs also get people interested in your writing before you publish - which is what you want. If you are not sure what category you fit into, you should start with a blog.
What if you have been writing a blog and now you want to turn it into a book? Save all your blog posts in a Word file and remove them from you blog. Removing or reducing the access works just as if you never published it. The posts could still be accessed (probably) by computer savvy individuals, but the number of people going to that trouble would not be great. You should leave a teaser of your work to attract others, and by all means keep blogging - just adjust your theme or focus.