I also don't quite understand the appeal of Rust for applications that can tolerate a GC. Other than perhaps borrow checking, I don't see the benefits over statically-typed, GC languages.

I used to code a lot in C++, but I've come to the conclusion that manual memory management is a cost that has to be considered seriously. e.g. one burden is that when you're declaring a field on a struct in Rust, you have to consider whether it needs to be a reference, value, automatic reference counted, boxed, if its a reference, what the lifetime is, etc. The only thing I miss about manual memory management is the RAII pattern.

Rust moves down a level of abstraction that IMO is not useful for most applications.