VSTS has a similar online text editor for editing and previewing markdown files.
I have a web hook that builds the markdown using mkdocs so we can have a nice web interface for others who do not have edit privileges.
VSTS recently released a wiki feature so I’m considering moving to that instead of mkdocs.
I think people see the value in wikis but it’s hard to sell git to someone who hasn’t used it before.
I’m always interested in this type of workflow but the problem that no one has seemed to solve is the local editing for a draft document for someone who understands markdown but not git.