Yeah, I think I get valuable feedback from character-players’ facial expressions that play and important part in my GMing. I’m not funny enough to rely on laughter.
Last time that I used Discord, it was prior to the addition of video conferencing. But starting a voice chat in Discord was always slightly unintuitive - you had to start or join a channel set up for voice. Discord considers voice/video conferencing a special kind of channel rather than a separate thing.
When I was roleplaying via the internet, the solution that worked best for our group was to use Google Hangouts for the video part, with the audio muted, and used Mumble for voice. Mumble provided vastly superior audio to any video service that we tried, with excellent clarity, very low latency, low resource usage and high reliability. Google Hangouts was a pile of garbage on all fronts, but the video part was “good enough” and works cross-platform.
Mumble’s problem is that it is a pain to set up a server (there are no free services), and a pain to get a client working. But once you have it working, it is very good.
These days, Discord is probably the most accessible voice and video conferencing platform, though as BigJackBrass says, the text part is more akin to IRC than a forum.