Doctors here don't use appointments but instead do a first come first seen arrangement.
What is the reasoning behind this? Is it because people may not show up on time?
Most always it is done as first come, first seen. It is cultural thing. Also, because even if there were appointments there would be long wait times. So, why make an appointment if you are going to wait anyway. Find out when doctor hours are and get there early.
Note: In the USA you can make an appt and see the doc. Then, there is a separate day for tests, x-rays, procedures, ect. Simple medical things that can take a days, weeks, and months in the USA to complete. While in the DR things can be done with one doctor visit, labs, x-ray, treatments, possibly same day. It depends on medical issues.
Regards,
PJT