I think the conflict here is that, for the "non-IDE" programmer, Rust's tooling is best-of-class (IMO). If your idea of an ideal programming environment is running vim/emacs/sublime/atom and maybe a terminal, Rust's tooling is great.
However, some programmers like an IDE more. Which is fine, but for this type of programmer, Rust still has a long way to go. There are some immature plugins for existing IDEs, and even a couple "rust-specific" IDE projects, but nothing near what (say) Java or C# have.
As a vim user I can attest to this. Rust tooling is better for me than any other language I have ever used. Only thing I ever wish for is a REPL, which is a big ask for a language like Rust.
Rusti isn't 'there yet,' unfortunately. It is forced to recompile the entire project for every line entered. Aa far as I know I also can't do things like set 'breakpoints' that will pause execution and drop me into the REPL, like Ruby's binding.pry.
This is a very hard feature for compiled languages, its just a con of this execution model (which is has a lot of pros).
I believe the playground is just a well-sandboxed Rust compiler. It doesn't have any of the fancy features of a REPL, such as allowing you to refer to the state of prior runs.
Rust has tools for package management (Cargo), documentation (rustdoc), linting (clippy), testing (the built-in test runner), and debugging (gdb and lldb integration).
It also has tools for code completion (Racer), build orchestration (Cargo again), benchmarking (the built-in benchmark runner), compiler version management (multirust), and automatic source code formatting (rustfmt, though this one's a WIP).
