Remember that there is no sign up, and that your mobile (phone number once registered via SMS OTP) is the only client their servers can trust.<p>Imagine a scenario where you were to get rid of the phone number and had sessions open on the desktop and the web. WhatsApp servers have no way of knowing where the phone number went or if it will be online ever again or if you continue to own the phone number, or someone else owns it. They need to route the msgs through that phone&#x2F;number combination all the time, because it&#x27;s the single source of truth.<p>Its security and privacy that&#x27;s preventing them from providing the feature you&#x27;re asking for.<p>If they detach individual user&#x27;s identity from a phone number, may be then they can be a true cross platform (web, phone, desktop) messaging app.