That doesn't tell me much about the usage scenario of complex numbers that would justify adding native support in programming languages. As a sibling comment said, builtin vector and matrix types (up to 4 dimensions) would probably be more useful.
I'll paste the same comment here as I did in the sibling; Why should complex numbers need justification? If you need to do serious computation, you need them. If you say Zig is not for number crunching which Java explicitly decided then fine otherwise searching for a reason for complex number tells me that you don't do any numerical programming which is fine but asking for justification makes no sense. Why is any other thing in the language justified?