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?