That is true if you already have Kubernetes. If you don't, then you still need to run and configure the Kubernetes' control plane (e.g. kube-apiserver, etcd, scheduler, etc). Doing that alone may exceed the complexity of a simple setup.
I say this as someone who has looked at Kubernetes a lot and wanted to use it, but could never justify it. I have concluded multiple times that docker compose is a better fit for my use case.
> However with Kubernetes your infrastructure will be ready to scale.
True, but for many purposes you aren't gonna need it.