I usually turn this around by saying supervisors work as if you had k8s inside your code. For example, when you have 20 database connections in your app, it is not something that k8s can manage, restart and automate, but supervisors provide exactly that, so you can apply the same principles on the “small” and the “large”.
Of course there are many gaps in this explanation but it can be a starting point for someone who heard very little about Erlang/Elixir.
