> I guess that's necessary to make tweets as commits from the web interface?

Yes! Just make your "gitweet" locally and git push. The login button is for lazy person like me to make git commits in the browser via the Github REST API. Sadly the written permission for OAuth apps is either none or all repos.

To use single-repo access, there are three choices

- github app

- deploy key

- fine grained PAT

I think they are too much hassle for non-tech user. The OAuth process is the most simple and smooth one. I hope github could provide repo-selection for OAuth, or allow specify which repo to connect with Github App.

I plan to add deploy-key based auth later. This could be also used for non-github services.