I’ve hit twice over the last year where it was needed. Though in one case, it’s because a server that was physically old enough to vote happened to be handling dhcp and dns. I set the other, only slightly less old, server to be primary on both but left the original functioning just in case with failed.

The main need I had was for a bank. Network functionality is obviously highly important there. Windows updates impacted the dhcp service on one server, which wasn’t an obvious thing till leases started running out the following morning. Multiple DC’s, so set up for HA to avoid issues in the future. It’s almost never needed but great to have when total uptime is key to operations.