Yes, learning anything is always a good idea, expands the mind. I'd say the same thing about any language. Too many people just stick to one, and they act like its going to solve the worlds problems if everyone just does it their way.
If a non-programmer asked me if he should learn C++, my answer would be "Only if you really, really want to. Otherwise Python, Javascript or Rust is probably a better idea".
If someone has a specific project in mind, C++ might be the answer, although probably in a minority of cases.
If someone just wants to expand their mind, then sure, why not. But there might be equally or more interesting things around, that's something that can only be retrieved from context as well.
Learning is always good, but there are subjective, qualitative nuances to be considered.
I feel like Rust does not belong in this list. Why would you introduce a non-programmer to Rust?