It helps you to earn more money.
For publishers that use Affiliate programs or PPC campaigns, it was scientifically proven that traffic which comes from search engines is more likely to click on your Ads than other source of traffic.
It helps you to build a community links.
As I said before, traffic that comes from SEO methods is sort of everlasting because is the one that places users in the place that they want to be, our site.
Get more RSS Readers, Twitter Followers, Face book fans for your website page.
SEO articles are the ones that build credibility and trust so, as a sign of respect, the users will follow you on twitter, subscribe to your RSS feeds and of course they will know that on your website they will find the information they need and start gaining social media power.