Booking policies are important because they help the service provider establish expectations with customers and protect the business, staff, and clients. A well-crafted policy can help the service provider communicate consistently with their clients about their expectations and the consequences if the clients don't meet them.
For example, a policy can help:
Protect the business If you have missed appointments, they can enforce fees for you or decline to book new appointments if you frequently reschedule, cancel, no-show, etc.
Establish boundaries A policy should communicate that the service providers time is valuable and that it is expected for you as the client to respect that time by providing adequate notice when you need to cancel, reschedule, etc.
Hold customers accountable the booking policy should communicate what will happen and you as the client should read all details and be held accountable for the information provided.