In the beta, it would be great to be able to make comments directly on the text (like in google docs)

For us, we use the GitBook as (public) internal documentation, because we want it to be open to other companies in our startup studio.

We think it's better to have something rather than nothing so we publish early, even if the article is not complete/perfect, and then collect feedback. Inline comments would help us collect direct feedback from team members directly on the text that needs to be improved