Showing how many users voted that a comment was helpful

I'm building a site with items that can be reviewed, and users can vote whether or not reviews are helpful to bubble the best to the top Amazon-style.

Amazon, Yelp, and almost everything else I could find shows the number of people who found the review helpful, often right next to the metamoderation button. (The one exception I found was Netflix, which I believe also uses "similarity" between the viewer and the reviewer to bubble reviews to the top, so I'm not sure how much "helpfulness" even comes into play.)

I'm wondering, if the site is already pushing the most helpful reviews to the top, what additional benefit providing the number of people who found a review helpful might have?