MattMack8989,
If you look at it this way, if you bring up all the 10 dell hosts with esxi installed and only local storage, you can create vm's on each one, but you can't "move" the vm's from one host to the other, even if you have vcenter managing each of the individual hosts. This is where you would need shared storage.
But if you don't have external shared storage like a nas or san, but have physical servers each with local storage, you can instead virtualize the hosts and local storage using vSAN, Nutanix, Simplivity. All do the same thing, they not only virtualize the compute part, but also virtualize the local storage so all the physical servers see the local storage as shared.
It's a great thing, but for us, we started using vmware before vsan came about. So we have the blade servers and external storage. I'd like to go to vsan, but
1. It's an additional per cpu cost.
2. It's simpler for us to upgrade/scale up/scale out our blades (compute) and san (storage) independently on our schedule and budget.
Sorry about the last part, i'll get off the soap box, the first 2 parts I hope answers your question.