It makes me wish I could pay a monthly fee to get better service, but in reality I'm sharing the same freely-distributed resources as any spammy Discord server. For example, I've been in Discord servers incessantly spammed by its users counting to the number 1,000,000, messages scrolling by like access logs during a DDoS. And I'm sitting there chuckling, "my server is in the same bucket as these people?"
At least Slack lets you pay them for an uptime SLA. I don't think I'd use Discord for a serious venture.
That said, surely your niche plays a large role in which one you pick. I'm somewhat in the gaming niche and Discord was a no-brainer. Gamers/teens are already on a dozen other Discord servers. Meanwhile, all of the Slack groups I'm a part of are professional.
The paid SLA is 99.99%, which is 1hr/yr downtime, but they've definitely missed that on our instance at least. The only thing I can really say that Discord is worse at is that discord has had a couple of total login server failures, but an individual server blipping out for an hour or three seems about equally common on both in my experience.
These compliance certifications.
Others (like myself) see these as much bigger advantages.
Fashion and style matter to lots of people. If 2 things are roughly equivalent, the one that's cool and looks neat is going to be the one chosen by the people who do care about those things.
On the other hand I use Slack daily.
Initially it was just easy to use VOIP with rich text chat channels. Now they've added in video calls and a video game store meaning they're more gunning for Steam and even less for Slack.
I do not see them as being Slack competing. They're too casually focused to be a threat in an enterprise environment.
Slack is very much setup for business use and integrations.
Discord has a bot API, but it's mostly focused around realtime chat for communities (like a community-focused Skype).
They're very similar, but serve different purposes and different markets
This is big for enterprise.
Slack has built a business model off commodity tech that was around for decades. It has happy customers who continue to spend money with them and a plan to continue growing their revenue with more happy customers.
Personally I just see it as a refresh of yammer or a business focused discord but at the end of the day someone in procurement is signing checks for Slack.
That being said, I'm sure the valuation is overinflated. The ARR ranges I've read don't justify it.
If you're feeling bold and want to speculate, I'd probably short it.
What are the benefits of using Slack over Discord? I know Slack has been around longer, looks more professional and has more tie-ins with work flow management tools but those seem like small advantages compared to how feature rich Discord is. Just genuinely curious as I prefer Discord for communicating with my coworkers about non-sensitive information but it doesn't seem to get any love outside of video game and internet communities.