It used your existing phone number as your identifier

Wait, people think of that as an advantage? For me, that has always been the reason I have refused to use it. It’s also why I never even tried Google’s Allo despite being a big fan. A chat application that isn’t using the phone network shouldn’t be tied to your phone number. It makes cross-platform support extremely awkward, and that’s noticeable in how poor What’s App still is for cross-platform use.