There are many advantages of hiring a WPF MVVM developer, including:
Increased productivity - WPF MVVM developers are typically more productive than developers using other frameworks, due to the separation of concerns and declarative nature of the framework.
Easier maintenance - Since the view and view model are decoupled, it is easier to make changes to the application without affecting the rest of the codebase.
Better testability - The separation of concerns between the view and view model makes it easier to unit test your code, resulting in fewer bugs.