I don't know that I would consider writing macros a sign of language expertise. I work on a large, intricate Rust project and macro stuff, while it does come up occasionally, is not what I would see as the "elite" bit of writing Rust. The best Rust folks I have seen understand Rust's type system, how it relates to the memory model and how those relate to the underlying machine.

I feared macros initially, but when I tried I was actually surprised by how easy they were. Way easier than Scala 2.x macros.

Rust has two macro systems. First it has declarative "by example" macros which I wouldn't give to an absolute beginner but they're very safe and give a flavour of meta-programming. A programmer with a good general knowledge of Rust, and a nagging feeling that there must be a better way to make these several almost-identical-but-not-quite new types they're working on can learn how to write "by example" macros and while learning probably won't set anything on fire. Rust even provides, out of the box, an easy way to see what the result was of your macro substitution.

Second, modern Rust has stable procedural macros. The procedural macros have essentially unlimited power, since they literally run inside the compiler processing the tokens of the program. Still, two kinds of proc macro, derive macros and attribute macros are fairly tame and, with due caution, merely competent programmers can experiment for themselves. It's really only the function-like proc macro that makes unlimited chaos likely and wants an expert. Stuff like whichever_compiles! (a macro which takes a series of code blocks and your program has the first one that compiled successfully...) is in this last category and is clearly toxic. Anybody who could write such things hopefully knows enough to do so only as an elaborate joke.