Hiring a Mercurial developer brings in an expert in one of the most efficient version control systems. They can handle codebase with utmost precision, ensuring error-free code management. Their expertise in handling complex projects, coordinating multiple coders, maintaining clean code history, and resolving conflicts is invaluable. They can also automate processes and create workflows, enhancing productivity. Their knowledge in using Mercurial's robust branching and merging systems allows for seamless code integration, fostering a collaborative environment. Thus, a Mercurial developer would be a great asset for efficient project management and successful software development.