Aren't those tiers just functionally accomplished by other technologies better suited? For instance, a Slack/Discord/Matrix with themed channels for people to t

Aren't those tiers just functionally accomplished by other technologies better suited? For instance, a Slack/Discord/Matrix with themed channels for people to talk and share relevant stuff about some hobby or topic for sharing among a group of friends, and then a public Twitter/Instagram/Tumblr that your friends may or may not follow and may be anonymous?