IRC does not support group voice & video calls, which is one of the primary features of Discord (and previously Skype, from which everyone migrated to Discord in the first place)

It's a viable system for the many open source software projects that collaborate over chat. Expo, Typescript, and Effect are relatively large examples. I'll participate there if available and I get locked out. Otherwise, I'll just use the stuff without contributing, no problem.

Kids these days...