Would it be possible to use Pulumi for "Playbook" style, one-off tasks? Like if I wanted to script up getting a Kubernetes deployment, scaling to 0, pointing the service to a maintenance page; would that be a sensible use-case?

Pulumi certainly can be used for many playbook tasks. Currently, the focus is certainly mostly on "desired state" applications, where you want to ensure some infrastructure is in a known state - not surgical changes outside of desired state. So most of the "playbook" style tasks in this mode would be to change the desired state to the form needed by the playbook step and drive a deployment into that state. Other workflows that are more surgical could be built with Pulumi though if needed.

I'll have a play with this. I'm curious, more than anything