> Probably half the macros I see could just be a function call.Yes, that particular breed of C macros would likely manifest in Rust as people just defining a new function. In Rust, you tend to see macros in places where "just make a new function" doesn't suffice for whatever reason; for example, maybe you need to define a dozen different structs that only differ by the type of one field, so instead of actually defining the struct a dozen times, you could just define the struct inside the macro and then `define_my_struct!(u8); define_my_struct!(u16);` and so on.
You also can't use Rust macros to "redefine" other unrelated pieces of code, so that's one less thing to worry about.