What kind of workloads are you running on it? Whoever has OpenFaas installed on your rpi, what type of functions are you running?
The real value I get is Infra as Code, and having access to the same powerful tools that are standard everywhere else.
I can drop my current (dedicated) hardware and go publish all my services on a new box in under an hour, which I did recently.
From my point of view, I already pay the complexity by virtue of k8s being The Standard. The two costs of complexity are 1) Learning the Damn Thing 2) Picking up the pieces when it breaks under its own weight.
1) I already pay regardless, and 2) I'm happy to pay for the flexibility I get in return.
(Disclaimer: I work for Canonical)