> This leads me to another thing that bothers me and that is where people think it's a situation of having to use e.g. Puppet or Ansible as if they're conflicting choices for the same tasks.

That's mainly because Ansible folks advertise it as a configuration management tool, while in fact it's a deployment tool. The former needs asynchronous operations, especially because a node that is supposed to be reconfigured can be temporarily down. The latter needs to be executed synchronously, with reports being read as they come by an operator.

There are several other operation modes that are useful for a sysadmin, like running a predefined procedure with parameters supplied from the client, or running a one-off command everywhere (even on the servers that are currently down, as soon as they are up), but we don't have many tools to cover those cases.