Alright. Now, let's say everyone is busy, and the maintainers have no time to review the patch. Who's going to remember that someone sent an email with some improvements a few months later? AFAIK There's no easy way to find all the emails with patches that weren't merged/(not) accepted/upvoted/downvoted/closed/etc. It's not easy to refer to the specific email; it's difficult to pinpoint the exact conversation around a specific change using git-blame. GitHub/Gitlab/etc. make all that a lot simpler.