Maybe the example I had isnāt the most suited, but Iām sure there are more that would have a better time encouraging sign ups. I see why a broad open invite group would be hard.
But lets say you run a amatuer football league, or your local branch of your political party, or your local AmDram group, etc etc. Or maybe you run a small business and need to communicate quick messages to your staff - basically any group that there is āflowā in which one becomes engaged, and has some form of organised structure in which information needs to flow.
Running out of examples, but I could totally see a space where it fits if itās made and advertised well. The āignore stuff of no relevanceā bit is also tricky, because people lose engagement and interest if the threads are filled with irrelevant stuff.
If you can reduce the hurdles of some of the more flexible tools (like Slack, and to an extent Discord), allow a more community based feel, like Discourse, plus the instant communication and ease of access of WhatsAppā¦ Then sounds good.