Pros Cons
The reviewer can be totally honest with their thoughts on the paper as they will remain anonymous throughout the process Providing details of the author may take some of the focus off of the work, when really the reviewer should be focused on the work alone
Risk of conscious bias, they might be tempted to give a more critical review to an article written by someone they consider to be a rival
Risk of unconscious bias from the reviewer, they may make judgements on the paper based on details of the author without even realizing
Some reviewers may use their anonymity to write reviews that are rushed, rude, or unfair, which they might not do if their name was being associated with the comments