IME, in large community servers (usually info dumps or LFG platforms like the video in the article) I almost never see it used. But in my smaller friend-focused Discord servers, there's always someone in the voice channels.

I think the greatest thing Discord did for gaming communities was make it so easy to get people together in a voice channel that everyone stopped using Skype. I tried for years to move people to Mumble/Vent/TS but it never stuck. But Discord managed to do it. I'd say voice is still the main feature that draws me and friends to the platform.