Space on a hard drive is finite, no matter how much it costs, and the size requirement makes it particularly unattractive for running in a VM, compared to a leaner OS.
I run only SSD in my desktop and I was running out of space for VMs. I decided to move a VM to my NAS and I discovered, happily, that it runs great on the NAS, connected over Gig-E. I moved the rest of my VMs over there and I really don't notice a difference in performance.