I think the most powerful feature of C++ is templating. Templating makes it very easy to write high-performance math code (no dynamic function calls, everything unrolled by the compiler...).

Just have a look at the state of the art math libraries in rust and compare it to something like Eigen or Cgal. The C++ code is way more flexible and expressive than the rust code. If you don't believe me, check how the rust libraries handle matrix implementations. Often you will find specialized implementations of 1x1 to 4x4 matrices but no generic n-dimensional matrix code.