Hey drumweaver, I will answer that for you. I also have a hub on RSS feeds that explains some of that, so you are welcome to read it.
RSS feeds, which a lot of people do not understand, is in fact one of the most powerful online marketing tools on the internet, if you understand how to use them.
They basically syndicate the content from your website or blog and allows multiple people to see the same content from you. Even more powerful, RSS feeds allow OTHER websites to show YOUR content. There is nothing more powerful on the internet than that. For example, if 50 website owners want to display your content, the RSS feed makes it easy for them as it shows all new and updated content and you never have to contact them to update their website. That's a big time saver for you and them.
It is a big viral marketing tool and anyone can subscribe to your blog just by adding your RSS feed to their RSS reader. It is true that they can just go to your blog or website to read your content, but RSS feeds expand the reach of your website to mobile devices that may not be able to display your website.
I hope this answers your question.