> It also puts a spot-light on the "your phone number is your username" policy.

I'm willing to bet that this decision is just jumping the gun by a month or two since usernames are around the corner (code exists, just not enabled. Can be used if built from source).

Though I haven't had a hard time converting (Android) users by using another app. Especially people that already use WA. The "other app" just comes off as normal. Apple is a different ball game because the walled garden, but that's also the weakness because you can't send photos/videos in group chats with mixed devices (but Signal can).