Sure there's lots of discussions on whether writers should blog. In the context of the "to blog or not to blog" discussion, blogging is considered one of two things: 1) Advertising or 2) A Distraction. Blogging can certainly do a great job at those things.  
Fox in Box
(Fox by Marcin Rybarczyk,
Box by Billy Alexander, via sxc.hu)

I know you have lots of other priorities like feeding your family or earning real money or showering once a week...blah, blah, blah...but as a blogging convert, I can tell you there are many benefits of blogging for writers -and for anyone - to consider.  

Seven Sweet Side Effects anyone could experience from blogging:

1.      Share your knowledge about, well, anything with, well, anyone who happens by. You love Health Food? Great tell us about it and enjoy acknowledgement from others who do too.
2.      Build community with other people who love the same things (Stargazing? Pickle-making?) Discuss the most current topics and share insights on solving problems. ("My pickles wrinkled!")
Rocks in Box
(Box by Billy Alexander,
Rocks by Karin Lindstrom,
via sxc.hu)
3.      Learn more about your topic (Crafting with Lint, perhaps?) from readers who have experienced similar situations, reassurance from readers who agree with you, and lessons from readers who disagree with your points. ("I would never add glitter to my lint!")
4.      Be creative. Especially if you're in a non-creative day job, like say an accountant or engineer, you may not get to be creative for most of the week.  Let yourself have a break. Creative thinking is needed in every job and will help you shine.
5.      Hone your writing skills.  Expressing yourself on paper (or screen) is important for any career and even in your personal life. Being able to write well makes the difference between others supporting your ideas or not. 
Writer in Box
(Box by Billy Alexander via sxc.hu)
6.      Photography skills. Blog posts need pictures, because humans are visual beings and search engine robots like to know a human wrote a post. Whether snapping your own or editing pictures with free software like Gimp, photo skills are great to have for work and for home. (Okay, I'm not great, but I had fun putting these things in boxes-->)
7.      Gain confidence. Even 1 follower is 1 follower and having someone interested in what you say feels great. You do actually know some stuff. You have value to add to the world. You are uniquely you. And you are wonderful! (That's the picture book version of a pep talk...)

Bonus #8. I forgot one! Excitement. Perhaps not everyone is as easily amused as yours truly, but I get a little rush when I get comments or a retweet. Life can be a little routine at times, and blogging is a great way to spice it up!

All for the low price of a couple hours a week. That's one of the best deals out there!