Hiring an Apache ZooKeeper developer can greatly enhance your distributed applications. They can ensure high availability, fault tolerance, and reliability of your system by managing and coordinating distributed processes. ZooKeeper developers can also handle complex issues like race conditions and deadlocks. Their expertise can help in maintaining configuration information, naming, providing distributed synchronization, and group services. This means your system operates smoothly, efficiently, and without data inconsistency, thus improving overall performance and user satisfaction.