And the difference is more useful in the more common scenario of editing code and checking it. Though those days, language servers like rust-analyzer do essentially replace cargo check.

Taking the alacritty project and modifying the source files to pretend something happened:

    > cargo clean
      Removed 1602 files, 545.8MiB total
    > cargo check 
    [...]
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 17.12s
    > cargo build
    [...]
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 23.04s
    > find alacritty_terminal/ -name "*.rs" | xargs-I{} sh -c 'echo >> "{}"'
    > cargo check
    [...]
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.00s
    > cargo build
    [...]
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.37s

I wish it was faster, but I will take the speedup that I can!