At first, @matrix was "just" a modern alternative to IRC to talk on GNOME channels for me.
But the more I use it, the more I enjoy it. Having your own instance is really pleasant.
Of course not everyone is a systems administrator, let alone a competent one. There is a real need for small managed instances.
For people insterested, Element offers Element Home, a 10-person managed instance: https://element.io/element-home
Alternatively, Etke offers to manage services for you: https://etke.cc/