I fail to understand why I shouldn't use my favorite editor, I'd call it a non-feature (useless, not available from the competion because it is useless).
It just depends on how you approach it, since I prefer to work local and upstream revisions with change notes, the main reason for revision control.
Given the featureset of github, it makes somehow sense, it just contradicts revision control to work directly in the repository.
As others have said, it's amazingly useful for quick and small changes. I don't see how that means someone's IDE sucks. I work on many projects and don't have all of them open in my IDE with the latest code always on my machine. This totally beats opening that project, running a `git pull` (which may take a while on an active project which I haven't visited in a bit), making the change, then committing and pushing.
On top of this, it's useful for non-technical people using these tools. Not everyone can move around through multiple repositories and pull down updates as easily as you or I. However, now they can easily help keep documentation up to date without leaving their browser.
I don't think it's at all related to the editor I use (I use vim anyway so I don't think that's the issue).
Maybe it's worth considering that others prefer different workflows than you or have different use cases?
You are doing some clojure work, you commit it, the unit tests run and fail. Clojure can tell you exactly what function failed with what data and it could commit a file for you to execute in your repl.
Using the ability to edit/create files through a webservice means the CI server running the Clojure tests could dynamically add or edit files showing the real failure over some pretty-print error message. You could check into the branch and open up user_104_error.clj and see the data that caused the problem.
When you solve the problem the CI server could automatically delete these files from the git repository, or maybe keep them around just to keep testing them.
Automated code modification into the version control system really could be interesting new ground in continuous integration and testing.
That and just last week I committed a file with the javascript url hardcoded to http://localhost/sit/js/api.js and wanted to change that back before anyone noticed.
GitHub has this feature, FWIW.
There will be a mail client next...