I recently typeset a (stunning looking) master thesis for a friend and she was able to edit the text while I dealt with formatting, setting stuff up, etc. (Well for that project, also big props to pandoc [1], as it easily converted docx to tex including footnotes!)

Otherwise it's nice, because I set up shared projects with good looking CVs for some non-tech friends and even a template to write nice looking letters/invoices and they know what to change and how and I could hide most of the stuff going on in template files.

[1]: http://pandoc.org/