A blog is a channel for you to connect with the world. A connection - a means of communication - where you can speak your mind on various issues that concern you. This is especially great for aspiring writers to sharpen their skills, and develop a bond and possibly an audience for future works.
As you might have realized, a weblog is also a fairly decent way of earning a little extra on the internet. However, it's not particularly easy - in fact, although 48% of bloggers are in it for the money, I'm pretty sure most of them don't receive a dime (due to time constraints and pageranks, and other factors that affect blogs). Hopefully, you will be the minority in this case and make enough money to get by (at least to support your blog's domain and hosting, if not more).
Blogs are also a great way to become an expert on something. I realize that I've discovered much more about technology as well as paid much more attention to certain things in music that I had never noticed before (I have two blogs, one for each of the niches).
If you despise writing, then I'd seriously reconsider getting a blog. If you're not a great writer, it's alright - in fact, I'm still not too great a writer, but I'm working towards it. If you've got inspiration, try not to rush headfirst into things.
And just one last piece of advice: as my cousin told me, "Blog and have fun first and everything else (for example, money, fame, etc) will come right along. Don't lose track of those priorities." Um, if you're blogging for business though, that might not apply to you.