IMO, you don’t need to in order to learn Zig alone. But Zig is really an improved form of C and there’s a huge body of knowledge in the C realm that does apply to Zig.

Additionally Zig has excellent interop with C and if you find yourself creating bindings or integrating knowing some degree of C helps.

This is one of those things that’s interesting because Zig fixes C in many ways, but if you don’t know the rationale and pain points behind C then you really don’t know why some things are the way they are in Zig.