I don't think whatsapp will change their protocol too much, as they'll break millions of clients installed in old phones.
The benefit for the company looks obvious to me: save money on call centre / community management. Deliver a service to millions of mobile users without requiring them to download your app (just adding a phone number to the agenda).
The benefit for the end-user: having a conversational interface with a system is probably the lowest barrier entry to that system for a human. Everybody knows how to chat using whatsapp, but not everybody knows (nor is willing to learn) how to use your "user-friendly" GUI.
The benefit for the company looks obvious to me: save money on call centre / community management. Deliver a service to millions of mobile users without requiring them to download your app (just adding a phone number to the agenda).
The benefit for the end-user: having a conversational interface with a system is probably the lowest barrier entry to that system for a human. Everybody knows how to chat using whatsapp, but not everybody knows (nor is willing to learn) how to use your "user-friendly" GUI.