I will have to admit that this GIT/SVN is a very elegant solution in the ideal world, but in my experience real world code gets very very messy. Teams get lazy and don't always give very detailed commenting in version control.

Startups may be better at this, but the corporate world is even messier with quick turned spaghetti code. Any markup in the codebase itself helps the next developer tremendously.

Personally, I find @mattbgates best practice to be very justifiable in practical use.