Of course there are reasons that your Klout matters on personal level...most people want to have some sort of influence. Also, the more influential you are, the more Klout Perks will be available to you. You can get Klout perks by achieving a certain score or by being influential about a specific topic. Though the idea behind the perks is pretty good, I have not found them to be all that interesting. Though I think Klout is interesting, in the long run it doesn't really matter all that much on a personal level.
Klout definitely matters if you are a business owner...especially a brick and mortar business. Here's why. People using social media are not scared to mention a brand. They will talk about their experiences, both good and bad, through social media. Influential people can have much more of an impact of what actually happens when they talk about it.
I have already read about a few start-ups tackling this type of application, and I can only imagine that we will see many more. Klout has already teamed up with Postling to notify an owner when someone influential is following them. Good information...but not nearly as powerful to a brick-and-mortar establishment. I like Klout and am quite interested to see how it progresses in the near future. Have you checked your Klout score?