Your static app won't scale. Once your kernel is saturated with connections, once your buffers are full, you will get packets dropped. Your app may crash unexpectedly so you need to run it in an infinite loop. And of course your static example is a simple echo app or hello world. That works fine from a toaster. In the real world we use databases where every store takes a significant time to process and persist. You quickly overgrow a single server. Then you need distributed systems and a way to do versioning so you use containers and then you need an orchestrator so you pick K8S because it's most mature and there are many resources around. And then you can even do rolling updates and rollbacks. Finally you use Helm, Terraform and Terragrunt and never look back. It works surprisingly good. I lost several years by learning all this stuff, it was difficult but it was worth it. I have more visibility into everything now thanks to metrics-server, Prometheus Operator, Grafana, Loki and I have two environments so I can update deployments in one environment and test, once tested ok, I can apply to live. No surprises. No need to run 5 year old versions of software and fear updating it...