Do you actually get 14 days of earning money? Or do the last blogs you post at the end of the week revert back to previous levels? Or the previous weeks blogs not rise in value? I honestly have no idea, but it does make a small difference.
You are correct that there are unquantifiable small side effect benefits: being noticed for your upvote value and receiving more followers because of it, and gaining additional followers from neoxian mentioning you in his blog.
Also whenever I want to challenge myself to do something I always set up stakes to motivate me, so having incentive to work your ass off for a week is usually a good thing. However, this is simply too expensive. I'll see where the market goes, and I hope @nulls makes money on this gamble, but I would bet heavily against him.