I've been working on turning a pretty massive scanned book into a git repo of markdown files, with multiple collaborators. Using sentence-per-line has been useful (compared to line-per-paragraph) because, even with / despite --word-diff , PRs are far more concise, and merge conflicts are more rare. From memory, with paragraph-per-line, I think a series of paragraphs, each changed, even with minor changes, kinda breaks git diff and GitHub diff.
Oh, wow... I hadn't even thought of the diff angle, but it makes all the sense in the world. I've heard some authors even start each clause on its own line. I'm not sure I'm ready for that yet.
