You're correct that biophysics isn't much physics, at least in my program. These areas depend heavily on the program itself. I am a Ph.D student at Johns Hopkins, and Biophysics is its own department. However, at say ASU, biophysics is through the physics department. Our curriculums completely different.
This same statement applies to medical physics. I know someone who does medical physics at SUNY Buffalo through the physics department. If you went to Duke, though, it'll be a different story.
These interdisciplinary fields will vary from school to school.
But your statement is a bit odd, as any job or program will involve physics, as physics is the base of the pyramid. You'll end up applying your physics degree in anything you do, whether it be an engineering job, biophysics, medical physics, any sort of physics.