Code reviews are one of the few ordeals worth doing. They catch problems and transfer knowledge. In a reasonably well run org (it doesn't take much) code reviews are easily a huge net benefit.

As for "reading closed tickets", you are right. It is silly. Alas, in apathetic orgs it is a reliable way to get some people know what is going on some of the time. And that particular ordeal keeps the tickets somewhat in sync with reality.