I agree that there is a difference between the actual history of a project and the writing of that history in a repository. We all make mistakes and rebase can be used to correct them. Fossil just takes the other view that we all make mistakes and we must live with them. I guess the choice of which to use very much depends on the circumstance. I use svn, hg and fossil choosing fossil more recently for my personal work for the simplicity of having code and wiki in a blob I can easily move.

On a side note I'd probably refrain from using the phrase "polished the chain" due to the euphemistic nature of 'verb the noun' statements and my natural British tendency to avoid talking about sex explicitly and thus think everyone is talking about sex implicitly.