Having a PhD in physics doesn't necessarily mean you've been exposed to the current state of the art in software development practices.
In my experience C++ is the default language in finance because of legacy reasons and because they don't know any better. This was only a couple of years ago and I saw some horrendously poorly written C++ code--virtually no comments, early 90's style ("let me tell you about the STL"), no comments for hundreds of lines--that was being used in production to value mortgage bonds worth tens of billions of dollars. The group I was in had switched to using Python with Numpy, and was much more productive for it.
In my experience C++ is the default language in finance because of legacy reasons and because they don't know any better. This was only a couple of years ago and I saw some horrendously poorly written C++ code--virtually no comments, early 90's style ("let me tell you about the STL"), no comments for hundreds of lines--that was being used in production to value mortgage bonds worth tens of billions of dollars. The group I was in had switched to using Python with Numpy, and was much more productive for it.