'cargo run' doesn't install anything; it just builds and runs directly from the source tree.

'cargo install' does install to (usually) ~/.cargo/bin/.

The useful difference, though, isn't in where things get installed, it's that a Rust binary doesn't really care where it lives, and most don't have shared library dependencies that aren't commonly installed already. So things tend to just work, unlike with Python venvs.

Cargo run just builds and runs the produced binary. It doesn't even install it