It’s not like anyone’s recommending you setup k8s just to use Postgres. The advice is that, if you’re already using k8s, the Postgres operator is pretty great, and you should try it instead of using a hosted Postgres offering or having a separate set of dedicated (non-k8s) servers just for Postgres.

I will say that even though the StatefulSet pins the pod to a node, it still has advantages. The StatefulSet can be scaled to N nodes, and if one goes down, failover is automatic. Then you have a choice as an admin to either recover the node, or just delete the pod and let the operator recreate it on some other node. When it gets recreated, it resyncs from the new primary and becomes a replica and you’re back to full health, it’s all pretty easy IMO.