I agree. I know some people, who are good at writing, who were going to opt out of another documentation project if Git was used as the means of collaboration

I agree. I know some people, who are good at writing, who were going to opt out of another documentation project if Git was used as the means of collaboration because they felt it was an unnecessary barrier to entry when a wiki is so much more straightforward. In the end we did use Git for documentation (pressure from devs), and in practice the non-devs tried to stay involved but ended up letting "technical" people do all the Git and diffing stuff, so it remained a practical barrier to involvement in the documents. People who are used to Git and development in general tend to forget that a lot of tools we take for granted, including text editors, terminals and command lines, are completely alien to non-developers and not everyone wants to learn that stuff for just one project. I've known developers struggle with Git too (when they don't use it often, or it's only used for 1 out of 10 of their projects), so I agree it can be a fairly high barrier.