It is used in a non-federated context as the underlying in a lot of places (NATO, Zoom, british Military, Grindr, Jisti…). Federated usage is mostly private chats that don't really want to advertise that they do use it. It is sad because public groups also just work, but I know clients are missing a few features that would improve usability/UX. Some people are working on that, cf https://movim.eu/ for instance.

Isn't this the sort of moment that pushes users off of Discord into alternatives? Maybe pragmatic/opportunistic users should establish new channels or servers and advertise them when the shoe drops on Discord.