It's more about authenticity and genuine interaction than etiquette. Efficiency drives us to shorter messages. Shorter sentences. Sooner or later, the human part of the conversation is stripped down to its bare minimum and only the useful information stays. It comes eerily close to talking to a computer.

Hi. When are you home. At six. Ok.

There is no room for the vague thing that comprises a 'real' conversation. That is, if you let this efficiency drive happen. I know I won't. WhatsApp is so popular here that it is assumed that you have it if you have a phone at all. It's so easy to message someone, the bar is so low that it could potentially be the most efficient communication tool.

Instead, most of the conversations I have on it are in group chats about the latest news, what's on tv, a funny picture or just joking around. Conversations that are "useless" but fun and genuine. You can use it as a pure and efficient communication platform, but I like it exactly because it's not serious most of the time. Then conversations are much more personal and authentic.