Hiring a Modernizr.js developer comes with several advantages. First, it helps in creating a seamless user experience across different browsers by detecting the features available in the user's browser. This feature detection is essential for ensuring compatibility with older browsers and allows developers to create fallbacks for unsupported features.

Secondly, Modernizr.js developers can enhance website performance. By only loading the necessary polyfills for the user's browser, the website can load faster and operate more efficiently. This can lead to a better user experience and potentially higher conversion rates.

Thirdly, Modernizr.js allows for progressive enhancement. Developers can create a basic version of the website that works on all browsers, and then add advanced features for browsers that support them. This ensures all users can access the website's core functionality, regardless of their browser's capabilities.

Fourthly, hiring a Modernizr.js developer can save time and resources. Instead of having to manually test the website on each browser and version, Modernizr.js automatically detects the browser's features. This can significantly speed up the development process and reduce the resources needed for testing.

Lastly, Modernizr.js developers have a deep understanding of browser inconsistencies and the latest web technologies, which can be a valuable asset to any development team. They can provide insights and solutions that other developers may not be aware of, leading to a more robust and future-proof website.