Nice. I thought that Zig would be a nice language for writing NIFs - but of course Rust would be good too. Cool!
So using C and Zig libraries without fully understanding them can be a death trap while in Rust as long as it doesn't use unsafe code you can feel pretty good about using it.
It's entirely the rustler project's effort (and goal) to wrap any kind of Rust program so that it will not bring down the BEAM under any circumstance, which they have done a great job achieving.