With the entire ongoing debate about paid links, is there a benefit to buying links with nofollow? Perhaps. What would be your argument to go with nofollow paid links?
For one, you can possibly get traffic from the link even if Google doesn't give it any love. Another thing is that it's good for branding. Furthermore, if you have a paid link, it's an endorsement.
But the bottom line is that many people agree that a paid link can still get traffic. As one person says, she gets a lot of traffic from her nofollow Wikipedia link, so it's proven to be successful.