ZSTs are a choice, if you're not benefiting from them in development time or correctness, why are you making that choice?

Rust isn't just C++ with static analysis. The safety is only about 1/3 of what makes me enjoy working with it. Even if I just consider the effort taken before I present something to a compiler, the trait system means I don't spend anywhere near as much time writing copy/copy assignment/move/move assignment constructors.

Some of that 2/3 will be me making choices like ZSTs, but I believe that's a result of it being necessary to grok the whole language and style and the idioms. If I just try to write C in Rust, it will be bad Rust and I'll have a bad time - but the same goes for just writing C++ as C with classes. I deliberately didn't say 'C/C++' in my ancestor post, because I think it's terminology that undermines claims of authority.

I do happen to have embedded experience, but avoid drawing conclusions from it because it is so different to more 'standard' systems development. If you can forgive a tangent: I avoid the whole domain now, because it feels like a ghetto. Standards are poor, tools are poor, pay is seriously poor. If you want to write embedded software, you probably have to work for a hardware company with hardware company's engineering culture and revenue model. That's a pretty crap place to write software in the west. I can't comment on comparing what like to do embedded development in Rust. Frankly, I hope I never can.