No one is trying to convince you to use C++. Obviously the data show there are tons of C++ jobs and this is something you can google yourself. And finance is not a "niche", considering it's like 20% of the US economy. I'm in finance and I write high-performance simulations and pricers. These things need to be predictable, fast, and the code needs to be maintainable. And yes, despite what the prevailing Go or Rust bros say, modern C++ is maintainable.