Assembly script is a lot easier to pick up than C++ and Rust; especially for people coming from a typescript or javascript language background (i.e. web developers). And it's not like you are going to get a huge performance benefit using Rust or C++ over assembly script. It's the compiler that makes things fast and the idioms. And basically the compiler toolchain is very similar for assemblyscript.
The only real difference with assembly script is that it's a garbage collected language. Otherwise, it uses llvm and the same set of optimizations you'd be getting with C++ and Rust.
The only real difference with assembly script is that it's a garbage collected language. Otherwise, it uses llvm and the same set of optimizations you'd be getting with C++ and Rust.