Telegram would be just wonderful were it being marketed as what it is. It's a gorgeous mass groupchat system.

Nothing private at all, but for that you get convenience.

And I would like something also private and still fit for mass groupchats, I don't know, perhaps, instead of encrypting messages for every participant have some kind of rotating symmetric keys for everyone, like with encrypted TV streams, signed by a smaller set of group moderators. That could fulfill the same role and also be peer-to-peer.

But a lot of things exist beyond our imagination, it's just that for something to be persistent someone needs to make money on it.