Discord's lack of lag in audio makes a huge difference for voice comms. I've only used it for gaming, but you can really tell the difference when you switch to the game's voice chat feature which has probably a third of a second of latency. And of course Zoom et. al. have a lot more lag and it really hurts the experience. In addition to low latency, the sound is also very good quality.
Note also that no messages in Discord, including individual messages/DMs, are end-to-end encrypted. This is precisely the same security issue that Zoom has (and Slack, and IRC without OTR).
Discord can and does log all messages through the system, and has many internal tools that operate on the plaintext. Anything you communicate through Discord you should assume any/all Discord staff may read.
They claim that the voice comms are e2e but there are no further details available (like where the keys are generated).
Discord's lack of lag in audio makes a huge difference for voice comms. I've only used it for gaming, but you can really tell the difference when you switch to the game's voice chat feature which has probably a third of a second of latency. And of course Zoom et. al. have a lot more lag and it really hurts the experience. In addition to low latency, the sound is also very good quality.