This.
Restarting an Erlang process and restarting a Docker container is not the same.
Let's say you create an Erlang process per request and that process crash, you don't want to restart the whole node, do you?
Application resiliency and Infrastructure resiliency are not incompatible, in fact, they are complementary.
Also, use libcluster[1] and horde[2], and you will never deal with leader election again. (which Kubernetes does not provide).
I've seen many Kubernetes Operators not handling more than one replicas, and that's a shame if you want High Availability.
[1] - https://hexdocs.pm/libcluster/readme.html
[2] - https://hexdocs.pm/horde/getting_started.html
Resiliency of a cluster with k8s or similar orchestration, AND resiliency of the individual nodes within that cluster, taking advantage of supervision trees.
(Also, to complete this picture and provide resiliency of the service as a whole, add load balancing across multiple availability zones.)