Because Storage Spaces Direct (S2D) uses both SBL and RDMA, active data can be located on other storage nodes without negatively impacting performance. As such RDMA is highly recommened when using S2D in conjunction with Hyper-V VM workloads.
Whether data locality is a good or a bad thing has turned into a filosphophical debate. Its true that data locality can prevent a lot of network traffic between nodes, because the data is physically located at the same node where the VM resides. However, in dynamic environments where VMs move to different hosts on a frequent basis, data locality in most cases require a lot of data to be copied between nodes in order to maintain the physical VM-data relationship. The SDS/HCI vendors today that choose not to use data locality, advocate that the additional network latency is negligible.