Commonly stated, except I think that statement is wrong. A PR is the thing that has the effect of sending emails to the team, it is the PR that leaves behind a webpage & summary of what has changed. It is the PR that is doing the work there, not the CR. Which implies, you can open and then immediately merge PRs without CR to get that same benefit.
CR does give others a chance to study code, and become familiar with it - but that is different from "keeping up to date."
CR does give others a chance to study code, and become familiar with it - but that is different from "keeping up to date."