There are many advantages to hiring a Facebook API developer. One advantage is that they can help you create applications that interact with the Facebook API in order to retrieve data or perform actions on behalf of users. This can be used to create apps that provide a better user experience or to automate tasks such as posting content to a fan page.
Another advantage is that a developer with experience working with the Facebook API will be familiar with its quirks and how to work around them. This can save you time and frustration when trying to integrate your app with Facebook.
Finally, having someone on staff who is familiar with the Facebook API can be helpful in troubleshooting any issues that may arise. They will be able to quickly identify whether the problem lies within your code or if it is due to an issue with the Facebook API itself.