Hiring a Microsoft Patterns & Practices developer is beneficial due to their extensive knowledge and expertise in Microsoft technologies and best practices. They can create high-quality, efficient, and secure software applications. Their understanding of design patterns allows them to solve complex problems effectively, improving your software's reliability and maintainability. They are well-versed in creating scalable and performance-optimized solutions, which can significantly enhance your software's functionality and user experience. Moreover, their familiarity with Microsoft’s recommended practices ensures your software adheres to industry standards, reducing potential risks and costs.