My experience in school was the best professors were in the physics department. I learned a lot in those classes. I never asked, "Is this useful?" Of course, it has been very useful, especially in understanding engineering problems.

The physics professors worked hard at teaching their classes, and they all supported graduate students. I think that is sufficient. I don't care if some of their research gives mathematical results that are not testable. That is what we call research. I will back those professors every time.

That is my opinion.