1. User can subscibe the content even to mobiles.
2. You and somebody else can integrate the content to your other profiles and other sites.
3. Content aggregators can list your content.
4. You can submit your content to agregation services like technorati, diggit, etc.
So, if you are producing freguently new content RSS feed will be essential to get readers.
it really is the new web 2.0 way to get users to subscribe without giving their details...some are hesitant now....its becoming very popular....i know one blogger who has 900 k subscribers...and is making money that would make you shreak.....cool huh.
I would be adding this to your blog asap. I works well in youtube!