You need rustup because it's the official toolchain manager for Rust. Here's why it's essential:

✅ 1. Multiple Toolchains

Rust has:

• Stable (for general use)

• Beta (upcoming release)

• Nightly (newest features, like edition = "2024")

rustup makes it easy to install and switch between them:

rustup install nightly rustup override set nightly # for this project only

Without rustup, you'd be stuck manually downloading, installing, and managing versions — painful and error-prone.

✅ 2. Automatically Configures PATH

rustup installs:

• cargo (the package manager/build tool)

• rustc (the compiler)

• rustfmt, clippy, etc.

And it ensures they're always in your PATH.

✅ 3. Project-Specific Toolchains

You can pin the Rust version for a specific project using rust-toolchain.toml, so everyone builds against the same version.

✅ 4. Easy Updates

rustup update

Keeps your toolchain fresh and avoids weird bugs caused by old versions.

In short: you need rustup to work efficiently with modern Rust projects — especially if they're using newer editions like 2024. Want help installing it or checking if it's already installed?