A few things that make Discord unfeasible for general purpose messaging...
The need to host a server somewhere. It silos info, makes that info less permanent and less findable. I've gone to all iDevices at home, so can't self-host.
It also doesn't have great visibility outside the tech worker and gaming worlds. I'm happy to use it if somebody sends me a link, but it's not the default for most people I know (except for those that game). Slack is a bit more common, mostly because of broad adoption at workplaces.
The need to host a server somewhere. It silos info, makes that info less permanent and less findable. I've gone to all iDevices at home, so can't self-host.
It also doesn't have great visibility outside the tech worker and gaming worlds. I'm happy to use it if somebody sends me a link, but it's not the default for most people I know (except for those that game). Slack is a bit more common, mostly because of broad adoption at workplaces.