It’s the seamless experience that is capturing. Why do so many people use GitHub? I would argue it’s because of the friction it removes from the many git related tasks. Emailing patches is fine but not something everyone is comfortable with due to the “extra” steps needed to compare/diff, and discuss the patch. There’s user friction involved. GitHub and other git context providers have greatly reduced the friction for these processes as well as consolidated them into one place with other tooling. This value add cannot be understated. I can email you a patch, but that does not provide visibility into any CI/CD I’m running. Nor does it connect the patch to an outstanding issue.