This depends very much on a project. Ideally you should have a good test suite assuring that a given revision is correct before merging it into the mainline. If

This depends very much on a project. Ideally you should have a good test suite assuring that a given revision is correct before merging it into the mainline. If this is the case then every commit on the mainline should be considered an acceptable branching point. The advice in the article certainly makes sense for the kernel, but could be an overkill for well-tested small and medium projects. Keep in mind that the kernel is a special case both because of its size and the fact that such a low-level and hardware-dependent code cannot be comprehensively unit tested.