Hiring a Gang of Four Design Patterns developer is beneficial due to their expertise in software design principles. These developers provide efficient, reusable, and flexible solutions to commonly occurring software problems. Their understanding of encapsulation, inheritance, polymorphism, and interface abstraction ensures high-quality, scalable and maintainable code. They can foresee potential issues and prevent them, saving time and resources. Their skills can significantly enhance the efficiency and reliability of your software development process.