Which are the two worlds it is the best of? Not the regular merge, because the best of that world is that you have individual commits that you can reason about

Which are the two worlds it is the best of? Not the regular merge, because the best of that world is that you have individual commits that you can reason about and bisect. Unless your branch history is full of junk, unfinished commits, etc. But in that case the policy should be to not publish such branches (or at least only publish them as WIP / scratch branches which will get cleaned up properly and rebased before upstream merge).