Nobody should be using C/C++ for anything new, much less using it as a teaching vehicle. That's just irresponsible at this point.

Not true. C++ is great for scientific computing. There is a huge number of mature libraries like Eigen. You can also painlessly use Fortran/C libraries like LAPACK, SLICOT and many others. Performance is top notch. It's multiparadigm so you can use OOP where it makes sense. It's a very complex language, but for scientific computing the C++98 subset is enough and IMO it's far cleaner than modern C++ or Rust.

C++ also has by far the best support for graphics (OpenGL/Vulkan) and GUI toolkits like Qt.