[NotEvil]

Actually pointless as online status is shown when you open the app.

And you have to do that fir checking messages.

[femiagbabiaka]

Depends on your reasons for showing offline. If offline is a proxy for “I am not here to check and respond to messages”, such as when you’re sleeping, quite useful. If not, and you’d prefer to be constantly offline for privacy reasons, less useful.

[livre]

You don't "show offline" in WhatsApp, either "online" appears below the contact name or nothing appears. Nothing doesn't mean offline, it means the person doesn't have WhatsApp running in the foreground, they could or could not be online (which most define as "using or not using the phone right now").

[femiagbabiaka]

It was a euphemism, but good clarification! Colloquially you can interpret the lack of online-ness as offline.