Yes, this is absolutely true.
In addition to the above, two virtual conferences I’ve attended in the last year have used Discord as their interface for attendees and speakers & organisers. It’s versatile, has a decent permissions structure & supports audio/video sharing. (Although both conferences chose to use Zoom for the actual talks.)
You can combine developers, users, fans having access to the same community (with some channels being exclusive for a given group and other being public). There might be a technical discussion about implementing a given feature or optimizing part of the code in one channel and related YouTube videos in a media related channel. Two examples are Leela Zero and Leela Chess Zero projects. Check them out, it's something you will never get on a platform like GitHub.
There is nothing like that anywhere else. It's very unique experience you will never get on GitHub, Slack or anywhere else.