The film was precious. Every gram of film had to be brought back into orbit by Eagle in lieu of some onboard instrument, backup system, additional fuel and air or sample from the surface.
In my work, I shoot a lot of photographs when I visit a project site during design and construction. My priority is not composition or aesthetics, it's documentation so that I can answer questions which I didn't know I would have when I went so that I can avoid another trip.
They sent pilots, to the moon. They had a couple of hours. That's all. Film allowed them to collect a large amount of data which hundreds or thousands of scientists could later analyze.
Some rocks are more interesting than others. But it's better to have the scientists decide which to take a closer look at on the next landing.