I think there's plenty of things that are not clearly defined here.
First of all, there is a difference between being a "physicist" versus being a physicist at an academic institution. Those two are not mutually inclusive, and one doesn't automatically imply the other.
Observing a physicist who happens to be working at an academic institution means that you are observing not only a physicist, but also an academician. The latter is not unique to being a physicist, i.e. a biology, philosophy, english professor might have the same type of responsibility as well.
Observing someone for a day doesn't really quite convey what that person does. A physics professor might have a large teaching load on the day you are observing him/her, and might do very little research work. Go another day, and he/she will be doing primarily research work and very little academic work. Observe me one day and I'll be sitting on my rear end in my office all day writing reports, preparing presentations, or dealing with safety issues and documentations. Observe me another day, and I'm doing engineering work at the experimental floor and you'd think I live there. Come again another day, and you'd think I'm an accelerator operator.
When we give students opportunities to do internships, what we hope for is not just that the students get to work in a certain areas and learn some science, but we also hope that during that length of stay, the students get a flavor on what it takes to do science, how science is practiced, and what it looks like to be working in such a field. This can't be conveyed accurately in just a day, or even a week!
Zz.