A distributed switch offers several enhancements over a standard switch such as centralized control plane and support for traffic monitoring features.
Because distributed switches are created and managed centrally on a vCenter Server system, switch configuration is more consistent across ESXi hosts. Centralized management saves time, reduces mistakes, and reduces operational costs.
Distributed switches offer features that are not available on standard virtual switches. Some of these features can be useful to the applications and services that are running in the infrastructure of the organization. For example, NetFlow and port mirroring provide monitoring and troubleshooting capabilities to the virtual infrastructure.
Consider the following caveats for distributed switches.
Distributed switches are not manageable when vCenter Server is unavailable. vCenter Server therefore becomes a Tier 1 application.