I miss ordinary conference calling being the norm. I like having a desktop IP phone.
You just need the dns, account and password.
This is a very different story from e.g. email – even though most people I communicate with use either Gmail or some hosted Outlook service, I don't have to on my side (with some limitations around deliverability etc. lately).
IRC the protocol is pretty good still, specifically with the ircv3 additions. It's the clients that are janky still. I still remember when Slack ran a free IRC bridge for their chats...