How can I make use of iterative "work in progress" versions of papers
Not sure if I understood you correctly, but if you need a better workflow for managing the progress and evolution of your drafts, then I think the question you've linked to actually answers your question.

A combination of git and modular LaTeX can help you to:


track changes in your draft(s)
make sure new versions (and new versions of new versions) start with everything that was in the version they were started from
merge changes between versions
split your draft(s) in such a way that it is easy to include different bits and pieces in different versions
greatly simplify collaborative work
reuse parts of your projects (e.g. git project setup, LaTeX macros/environments/styles, any compilation scripts)
and many more things