I’m sure there are countless other benefits. But how many layers of abstraction, services and things that need configuring are their compared to basic RAID to get support for magical hard disks that can be yoinked without affecting workloads?
You get basic loadbalancing, health checks, centralized and nearly out of the box logging and monitoring and tracing.
You get a streamlined build process (create a container image, have an image build, create your helm chart, done)
Your RAID commment is quite far away of what k8s makes k8s
These things aren't mutually exclusive though. I've spent the last few years working with kubernetes at work and running a 'simple'(but with tons of containers and weird edge cases / uses) unraid server at home for all of my needs. At some point I flipped over from 'jeez kubernetes is just too much, almost nobody should ever use this' to 'wow I have to migrate 99% of my home services to a cluster, this is driving me nuts.' I haven't quite gotten around to that migration, but I do think that k8s cluster for services / temporary storage / parallel jobs and separate unraid box that runs NFS (and doesn't do much else) is going to be a great setup for a home lab.