Git rebase loses history, then why rebase?

I've been looking into rebasing with Git over the past couple days. Most of the arguments for rebasing say that it cleans up the history and makes it more linear. If you do plain merges (for example), you get a history that shows when the history diverged and when it was brought back together. As far as I can tell, rebasing removes all that history. Question is this: why wouldn't you want the repo history to reflect all the ways the code developed, including where and how it diverged?