Well they are full medical doctors, so see, and treat patients, carry malpractice insurance so you have some one to sue when they miss your cancer.

If it were just about reading the films, the tech who does the procedure would read the films. To be effective at a tech job you must know what you are looking at so that you can tell if you have successfully captured images for the doctor's report. If something looks off they may need to take further measurements and images.