in doing preparatory refactoring, adding the feature, adding tests, and his can be easier to review because the scope of each commit is smaller.
This is the use-case I hadn't considered. And it makes sense now that I think of it. Though I personally haven't come across it, since I don't typically work on multiple, cascaded features at a time. Most of my work as been with waterfall models, so I can understand that other approaches may indeed have cascading features in parallel.
Thanks!