Is there any real business going over discord & telegram? I've only seen scammer, illegal porn and conspiracy believers sell through those channels. Legit Influencers are usually using patreon, onlyfans or similar platforms.
I also know a professional* dungeon master who uses Discord to keep customers organized. I'm sure he could accomplish this coordination with e-mail and a spreadsheet, but Discord seems to cultivate community as a side-benefit.
*No, this isn't his fulltime job, but it seems to justify the amount of time/brainpower spent on Game Design/RP Writing efforts. And, yet again, charging folks a bit of money for membership puts them on their best behavior.