Safety and speed are the big words on the box. Usability is harder, because it's somewhat a matter of opinion. As someone who has professionally worked with the expression based Haskell, Erlang, Elixir, and OCaml, I find Rust to extremely expressive. If you come from that camp and feel that OOP is a bad toolkit of abstraction and that higher order functions, typeclasses, type parameters, and ADTs are much more powerful, then I think yes, Rust ticks all the boxs.