Discord basically started out as "Slack for gamers", and very quickly (IMO) surpassed both Slack and Skype in terms of functionality. I don't have to have a different account for every server I'm in unlike Slack, and their video and audio calling has always been much more stable than anything I've gotten on Skype.
With that in mind, I would've thought that their next plan would be to improve on what they do best, and try to market to the professional markets and take Skype and Slack head on. Instead they seem to be veering off and doubling down on the gamers. Judging by the number of people I see who have it, I imagine the profit from Nitro may be enough to keep the company going, and the Slack crowd won't be as lucrative as the opportunities from taking some of Steam's marketshare.