I don't think being able to run commands across multiple servers or instances is the greatest feature....at all.

I use it to complete day-to-day tasks, troubleshooting (standalone and cluster), gathering metrics, document server configurations, create report on server config and performance metrics for clients. I use it to access information when I don't have permissions through the GUI (e.g. if you don't have Local Admin rights to view all processes via Task Manager, Get-Process cmdlet still works for you).