Rust gives us 3 things we needed, and it says so right on the website: fast, no segfaults, thread safety. Additionally, it's community is top notch. We've found the language to be great to work with, especially when you're refactoring. The type system makes it clear where it's possible for the code to fail, making it easier for us to reason about keeping the supervisor safe.
I wrote this while I was evaluating languages for the early habitat prototypes: https://medium.com/@adamhjk/rust-and-go-e18d511fbd95#.d35imt...
Like most languages idiom is learned while working with the language. Something I've found for instance is to try and use Iterators to get around sharing rules as they can encapsulate sharing patterns in a lot of cases.
The specific modules you mentioned are for multi-thread support, those are only necessary for sharing memory between threads.
Anyway, I think this is off-topic for this thread.