While I think video/audio conferences are probably more efficient than chat conferences, they also are a lot less accessible for folks that aren’t native English speakers, or are impaired in other ways, or just being shy. Chat also has downsides (especially for slow typers/readers), but I think it’s still a better solution.
I guess you mean the relay bot; the bridge has been down since somewhen last year already. The problem seems to be that the relay bot got kicked/banned again and again from time to time. Seems like Libera.chat is not a good place if you want to bridge to other forms of chat communication 
I’m wondering whether another IRC network would be better suited for this… (When we back then decided to switch from Freenode to Libera, OFTC was another candidate. Does anyone know whether there’s a working Matrix-OFTC bridge? According to Bridged Networks - Matrix IRC Bridge there is one. Maybe we should switch from Libera to OFTC so we can re-establish a Matrix-IRC bridge?)