Discord was awesome for communication an administrative bulletins, you could check at a glance everyone who was online and join calls in a single click.
Also we had text channels for specific projects, and for a in-depth discussion of a specific thing we created threads in the same channel, anything of importance could also be pinned down.
With that out of the way, I think if done correctly, It works just fine, It's a different medium than a forum, since the last is used for future reference, and the former is for on-demand discussions.
Also any platform can be shitty If the wrong person is holding the reins (i.e. Github issues boards)