I have (semi-daily) and would say it’s somewhat close to being day to day usable. They recently added Safari-style back and forth gestures and you can choose to arrange your tabs vertically (though not in a tree).
The main thing preventing daily driving is that it’s not in the App Store yet, leading to it not being selectable as a default browser. I also experience occasional crashes with hundreds of tabs open.
Everyone on the planet is using IPv4 and the internet, yet the understanding ends at 'what is a LAN and what is a port' for a shocking portion of developers. Not knowing about federation[0] doesn't seem so bad.
[0] Most likely this is referencing the term and the structural pattern; as you correctly pointed out, the concept is quite widespread.
I bridge Signal/Whatsapp/Telegram and you can absolutely start chats through the bridge bot. It might be a little inconvenient, but for the rare occasion I do need it, it works absolutely fine.