Only a single Client for all his chat needs. XMPP aka Jabber protocol describes a thing called XMPP Transports. The idea behind that is simplifying the chat client by moving the client logic for different IM&P networks into the server.That means the client only needs to know how to speak to a XMPP server and can talk to all IM&P networks the server knows. That is Jabber for sure, but could be ICQ, MSN, Whatsapp, Facebook chat and YouNameIt.The benefit is, that you can receive your Whatsapp and other chat messages with only one client. The transport is already coded - e.g. GitHub - stv0g/transwhat: A gateway between the XMPP and the WhatsApp IM networks That means even today that is possible but you need to use the transport on another server besides IM&P. If Cisco would incorporate the Transport support (e.g. through plugins/cop.sgn installs) into its server, more people would use it.
NextPlane is an nice service but works with a different purpose. They sort of take the burden of open xmpp federation away from the client in terms of security/spam and compatibility. They actually federate your domain for your by asking you to point your DNS entries to their servers. But that only works with others that want to federate, too.There's networks out there that don't want that. Whatsapp and Facebook chat are actually XMPP based but don't federate at all. You cannot chat with someone from Whatsapp unless you have a Whatsapp account (and use the Whatsapp app).With my idea implemented a user could chat with all his whatsapp buddys within jabber.Benefit 1) No seperate app per service needed (walled gardens) - only Jabber.Benefit 2) Chat from all your devices that run Jabber - PC, MAC, IOS, Android...Benefit 3) higher usage of Jabber Client for Cisco since it's becoming the center of IM for its users.An actual downside is that by using transports you need to store the credentials for that other service on the Jabber server. But privacy is usually not a whatsapp or facebook users concern.