The good part for the patient is that it is a constant expense for the budget.
The good part for the therapist is that it is a constant income for the budget.
It just works well for some and is the preference of some. It's something to decide if it would work for you in the long run.

I just count on $400 a month as a constant therapy expense. My therapist doesn't have as strict a policy, although it is posted that patients are responsible for a cancellation without at least a 24 hour notice. She hasn't held me to that, and once I insisted on paying for the cancellation because I cancelled as I was driving there and knew it was avoidance. She set aside that time for me and I ditched her. She tried to give it back but I insisted and it was included on the check for 2 weeks of therapy, so she was stuck with it