Hiring an iPhone SDK developer offers several advantages. Firstly, they have specialized knowledge and skills in using the Software Development Kit (SDK) provided by Apple for iOS app development. This ensures that your app is developed according to Apple's guidelines, enhancing its chances of approval on the App Store.

Secondly, these professionals are proficient in programming languages like Objective-C and Swift, which are critical for the development of iOS applications. They also have a deep understanding of the iOS platform, user interface, and user experience design, which ensures the creation of high-quality, user-friendly apps.

Thirdly, iPhone SDK developers can offer innovative solutions and ideas. They stay updated with the latest technological advancements and trends in the iOS ecosystem, which they can integrate into your app for a competitive edge.

Fourthly, these developers can provide end-to-end services, from initial conceptualization and design to development, testing, launch, and post-launch support.

Lastly, hiring an iPhone SDK developer can save time and effort. They have the expertise to tackle any technical issues that may arise during the development process, ensuring a smooth, efficient process. This can also lead to cost savings in the long run as potential pitfalls and delays can be avoided.