It's not as effective as you imagine. Noise radar can still operate when the return signal is below the noise floor. It's very difficult to jam because the jamm

It's not as effective as you imagine. Noise radar can still operate when the return signal is below the noise floor. It's very difficult to jam because the jamming is uncorrelated with the noise signal. The low power levels make it harder to detect even with modern direction finding / interferometry arrays.