Hiring a Formal Methods developer is beneficial for creating robust, error-free software systems. They use mathematical techniques to design and verify software, ensuring correctness, reliability, and security. Their expertise helps in identifying and rectifying potential issues during the design phase, reducing the cost of fixing bugs later. They are crucial for critical systems like aviation, healthcare, or finance where errors can have significant consequences. Therefore, their skills can enhance the overall quality and performance of your software, saving time and resources.