If they weren’t all insane, twitter’s format has value for following real time events. For sports, for example, following a personally curated selection of sports reporters makes it a lot easier to keep up with transactions across the leagues I care about.

Reddit’s is better for discussion of those events, but not everything gets that far.

Facebook’s is supposed to be for actual friends to keep up with what’s going on in each other’s lives. Obviously it’s not actually talking, and you still want to do that, but it makes it easier to keep up with a larger group of people.

The problem with all of them is that they’re owned and run by insane shitbags, so they’re not worth the trade off. And the problem with fediverse alternatives is that they all rely on network effect to have their value. But in theory they each have a place, which is how they all managed to coexist despite the strong constraint of needing volume to serve a purpose. They serve different uses.