Points are often presented as a proxy for trustworthiness. They're even implicit on sites like HN where certain features only become available once you've crossed a threshold.

It's a bad tool. I always think of the Bill Bur joke talking about Netflix going from 1-5 stars to thumbs up/down. "It's like.. stubbed my toe.. thumbs down. Hitler.. thumbs down. There's too big of a gap in 'thumbs down.'"