The YS designer Aadesh Padave says, “(UX project design brief) provides a clear understanding of the client's needs, goals, and expectations, which helps us in the design process and ensures that the final product or design is completed as per the client's requirements.”
So, it is safe to say that the main benefit or power of UX project briefs is that it removes any confusion, reduces the risk of errors, saves time and resources, and helps you complete the project within the budget.