No, I agree that a package manager or app store is indeed safer than either curl-bash or a random binary. But a lot of software is indeed installed via standalone binaries that have not been vetted by package manager teams, and most people don't use Nix. Even with a package manager like apt, there are still ways to distribute packages that aren't vetted by the central authority owning the package repo (e.g. for apt, that mechanism is PPAs). And when introducing a new piece of software, it's a lot easier to distribute to a wide audience by providing a standalone binary or an install script than to get it added to every platform's package manager.