They are for altitude loss, and proper alignment when the course change exceeds
120 degrees (the limit is 90 degrees unless the intermediate segment is
lengthened to accommodate a course change of 91 to 120 degrees.)

Michael 182 wrote:

What is the reasoning behind the required course reversal in many
approaches? It's hard to believe that I will be safer flying the racetrack
and then the approach to the runway than simply flying to the IAF and
proceeding inbound - especially with GPS guidance. I have no problem flying
the full published course, done it many times, I'm just curious why they are
designed that way.

Michael