Hiring a JAX-WS developer is beneficial due to their expertise in creating web services in line with the Java API for XML Web Services. They can develop, build, and maintain complex web applications, ensuring seamless communication between different software applications. Their skills can enhance interoperability in your software infrastructure, leading to more integrated and efficient systems. Furthermore, they can effectively handle SOAP-based web services, providing secure and reliable data exchange, which is crucial for business operations. Their knowledge in XML and HTTP protocols can significantly improve your web services' performance and data handling capabilities.