Orchestration/install/setup scripts are usually run while nothing else is running. Bash is not ideal for this. But it's not ideal for almost everything. Still making things idempotent-ish is better than bailing on every recoverable error and making the admin do the cleanup manually so the script can finally do what it supposed to do.

(Of course a few years ago immutable infrastructure was the rage, because it means if the script runs once, pack it up as a VM and you're done. And that's how the docker sausage images are made.)