The obvious reason for the majority of this is --- They are required to by regulation. Any company flying big jets has no choice because the aircraft is certified for two pilot. We have the same thing with our E120s here at AMF. It's required.

Most corporate operators fly two crew, even in single pilot certified aircraft, because their insurance carriers require it. Aerial photography would do it because you have two separate tasks going on that could actually conflict with one another; one to fly and one to take pictures. One is looking around the sky and one is focusing on the ground, not exactly something you would want only one person doing.

It almost seems to me that you have the impression that PIC experience isn't important. The Strategic Air Command came to the opposite conclusion several decades ago.

When bombers were piston powered, pilots would spend a short time flying right seat and then move over to the left seat as the need arose. The planes were relatively simple (comparable to any piston twin or small turbo prop today, in terms of systems complexity) and there were no issues.

When large jet aircraft came on the scene (B-52, KC135) they found that pilots with little time being the primary decision maker became overwhelmed when things didn't go quite as planned. They developed a program in conjunction with Air Training Command called ACE. This stood for Accelerated Copilot Enrichment. They would take B52 and KC135 copilots (first officers in the civilian realm) and send them out in trainer aircraft (T37s and T38s; I personally have about 250 hours T38 PIC time from the program) as PIC to fly all over and get experience having to make command decisions such as dealing with weather and aircraft malfunctions (both inflight and correcting them once on the ground.)

They found that when these pilots then upgraded to PIC they were much better prepared to deal with situations that came up during missions in their primary aircraft.