The handbrake is still entirely mechanic, and is your emergency brake in case the brakes fail (the same would be the case on a regular car). Fortunately, I've never had that experience yet, and while I've heard the stories, I am still convinced the combined steering, braking and suspension system is a mechanical superior system, even if it requires more maintenance. I'd concede, that from a maintenance's perspective, it's an inferior system. Which is probably why Citroën abandoned it.