The key point is that Google figures out how much it makes by sending people to a site, and ranks the sites based on that metric. So just like Adwords, there's no getting around the fact that paying Google more (by bidding higher, or on more frequent events) will get you better placement, and therefore more traffic.
I see this as Google getting into the affilate marketplace, and integrating the adwords buying (which many many many affiliate marketers use) and affiliate payout into one financial transaction.
Hmmn, thinking about this more, it's actually cutting out the middlemen in a vast number of affliate transactions-- those that are entirely reliant on adwords buys instead of eyeballs coming in through a particular publisher. Now you can buy affiliate clicks on Google's entire network, instead of cutting individual deals with lots of sites and dealing with the administrative overhead of managing affiliates.
Smart.