Most of the diners and travelers who rate restaurants on this site do so simply because of their passion for delightful dining experiences and their disgust with the disasters.  They have confidence in their opinions and not only want to share them with their peers, but also know that they always get back much more than they give, since they have the benefit of the opinions of all the other members of this community when they're making their own travel plans (or even planning to dine out in their hometowns).  For these folks, seeing their ratings posted on the site is its own reward. 

But we decided to show them a little extra appreciation, on behalf of everybody in our community, with some unanticipated and nominally valuable gifts.  Now that we're growing as fast as we are, we can expand those ideas and make them available to everybody, not just a pleasant ex post facto surprise.  (If you look at this program in that light, as a nominal reward and some recognition for your ongoing participation, and not as a BOUNTY or BRIBE for rating restaurants willy-nilly just for the points, you'll be on the right track.)