While I'm definitely against the idea that mass is everything for a platform, something I definitely miss was the viability of "local" and/or "regional" stuff on Twitter due to the absurd mass it had.
Over the past few years my life has become more "local" and less "generally online" lately (somehow despite the pandemic), and I've been hesitant to bring that to my new platforms of choice because it feels unlikely to be relevant to anyone who'd see it.