Wouldn’t it be cheaper / less complex to scale vertically (eg a large workstation or medium size bare metal server) instead of using clusters? My understanding is that clusters are primarily useful when you want to share a resource from a pool across unpredictable usage, which becomes a moot point once the cluster is personal.
Scale isn’t the only reason. Sometimes you want resource isolation and self-healing, something that is useful if you want a personal swarm of AI agents.