REALLY IMPORTANT ANNOUNCEMENTS regarding my daughters' exams and schooling etc are in Telegram as well, sometimes WhatsApp. Some schools are well aware of the problem and have spent hundreds of thousands of dollars developing an app that isn't even an app, so now we have to head into yet another app-site to pick up the kids and get updates on schooling.
The good thing about Discord at least is I can be sure to ignore 100% of it and opt in any time I like.
The thing about emails is if I get too much spam from someone, I can unsubscribe. Same with social media. But I can't just block the gullible spammer uncle.