Discord has a business model: Get people engaged in a community, sell them Nitro so they can boost their communities [1][2]. The "buy benefits for you community" scheme is wildly successful in mobile games, so I wouldn't be surprised if it works well for Discord.
The fact that they are trying to sell/IPO is pretty strong evidence that they are not profitable, I think. But regardless, I will give them massive props for not just doing the ad thing, which is the last gasp of this style of startup before they finish circling the drain. Lookin' at you, Imgur.
I would in all honesty give them even bigger props, as someone who used to be but isn't a fan anymore. They tried to add a game store a la steam into it but realized it didn't get the engagement they'd hoped for so they stopped putting time and effort into it and shut it down.
My first impression when they first added it was that they'd just shove it down people's throats and keep trying to make it work.
I hope I'm not wrong about them getting rid of it again and I've just gotten used to tuning all that out when using discord.
This is what flailing around trying to find a business model looks like. If Imgur was profitable without those ads, they wouldn't be abusing their users like this.
The second they try to monetize discord like a mobile game is the second all of my friends stop using it and hop to the next silicon Valley chat app that pops up