Exactly. And at least Cargo will refuse to download a crate which has been yanked. So any crate which has been discovered to be compromised can be yanked, preventing further damage even when someone has already downloaded something which depends on it.

Building packages with up-to-date dependencies is also vastly preferable to building against ancient copies of libraries vendored into a codebase at some point in the past, a situation I see far too often in C/C++ codebases.