Hiring a JAX-RPC developer is beneficial for building and maintaining Java-based web services. They have expertise in Java API for XML-based RPC (JAX-RPC) which enables building of SOAP-based web services and clients. They understand the complexities of XML and SOAP protocols, ensuring efficient data exchange between applications. They can also leverage the interoperability feature of JAX-RPC to communicate with non-Java based services. Their skills can contribute to robust, scalable, and secure web services, thereby enhancing your business operations and customer interactions.