If they intentionally want it to be in secret or limited in scope then that's indeed a different issue that won't be changed by this. Nostr is at least the one thing everyone should have in common though, so it should help if they aren't intentionally making the chats exclusive. I'd say at a minimum that those who do communicate on Nostr owe nothing to those who don't since it naturally seems like the best fit for the official channel. You will never be able to force people to not use other channels. But at least having a Nostr option leaves the ball in their court instead of everyone else to use a number of comms outside of Nostr.