Hiring a Mongoid developer is beneficial for businesses looking to leverage MongoDB in their Ruby applications. Mongoid, as an Object-Document-Mapper (ODM) for MongoDB in Ruby, provides a robust and flexible solution for data modeling and management.

One of the primary advantages is the developer's proficiency in dealing with schema-less databases like MongoDB, which can handle large volumes of data and diverse data types. This facilitates scalability and flexibility in application development, particularly for applications that need to adapt to changing business requirements.

Mongoid developers also bring expertise in creating complex queries and indexes, enabling efficient data retrieval, and enhancing application performance. They can model relationships between objects, implement inheritance, and employ powerful validation rules, ensuring data integrity and consistency.

Furthermore, the developer's familiarity with Ruby and Mongoid can lead to cleaner, more maintainable code. This is because Mongoid's syntax is very Ruby-esque, allowing for more readable and idiomatic Ruby code, which makes the codebase easier to understand and manage.

Lastly, a Mongoid developer can help in optimizing the performance of your MongoDB database by correctly leveraging the features provided by Mongoid, such as eager loading and atomic operations.

In conclusion, hiring a Mongoid developer can provide you with an efficient, scalable, and flexible solution for managing your data in MongoDB, while also ensuring the maintainability and readability of your application code.