I have taken a course out of this book (in fact, Asmar is a professor at my school, though interestingly enough he did not teach the course...). It is a great book, and I would say even if you do not take the course, definitely buy the book! It is a great reference and is fairly cheap if you get the paperback version. This was by far my favorite and most useful math course as a physics major. However, I took the class as a first semester Junior and it helped me immensely with upper-level E&M and Quantum. I think having the formal foundation for PDE's is pretty indispensable for any physics major. You will learn a lot of tips and tricks for solving PDE's using this book. A lot of it you may have seen before, but I don't recall ever solving the heat equation using a Fourier Transform, even in thermo. Also, this is where I first learned to solve PDE's using eigenfunction expansions.
In other words, I think it is useful.