I feel GitHub gists are a very good store for data: writable, versioned, shareable and read-only for non authors, workable, support for arbitrary data including binary
I tried that. The problem is that you will always need a middle-end (a separate server between your stand-alone front end application and the GitHub server). You can't just distribute a stand-alone app and let it talk to GitHub directly. Or well you can but only if you get a token with *FULL* scope for all repositories. What I as a developer need is a scope for only one repository. That's how stand-alone and especially browser-based applications can remain safe. You don't want to store tokens with full permissions in multiple apps.